diff --git a/src/test/java/net/hostsharing/hsadminng/hs/office/usecases/HsOfficeUseCasesTest.java b/src/test/java/net/hostsharing/hsadminng/hs/office/usecases/HsOfficeUseCasesTest.java
index 57ceef0a..97b76dc3 100644
--- a/src/test/java/net/hostsharing/hsadminng/hs/office/usecases/HsOfficeUseCasesTest.java
+++ b/src/test/java/net/hostsharing/hsadminng/hs/office/usecases/HsOfficeUseCasesTest.java
@@ -1,6 +1,7 @@
 package net.hostsharing.hsadminng.hs.office.usecases;
 
 import net.hostsharing.hsadminng.HsadminNgApplication;
+import net.hostsharing.hsadminng.hs.office.usecases.debitor.CreateExternalDebitorForPartner;
 import net.hostsharing.hsadminng.hs.office.usecases.debitor.CreateSelfDebitorForPartner;
 import net.hostsharing.hsadminng.hs.office.usecases.membership.CreateMembership;
 import net.hostsharing.hsadminng.hs.office.usecases.partner.CreatePartner;
@@ -61,12 +62,30 @@ class HsOfficeUseCasesTest extends UseCaseTest {
                 .keep();
     }
 
+    @Test
+    @Order(2011)
+    void shouldCreateExternalDebitorForPartner() {
+        new CreateExternalDebitorForPartner(this, "Debitor: Billing GmbH")
+                .given("partnerPersonUuid", "%{Person: Test AG}")
+                .given("billingContactCaption", "Billing GmbH - billing department")
+                .given("billingContactEmailAddress", "billing@test-ag.example.org")
+                .given("debitorNumberSuffix", "01")
+                .given("billable", true)
+                .given("vatId", "VAT123456")
+                .given("vatCountryCode", "DE")
+                .given("vatBusiness", true)
+                .given("vatReverseCharge", false)
+                .given("defaultPrefix", "tsx")
+                .doRun()
+                .keep();
+    }
+
     @Test
     @Order(2020)
     void shouldDeleteDebitor() {
         new DeleteDebitor(this)
                 .given("partnerNumber", 31020)
-                .given("debitorSuffix", "01")
+                .given("debitorSuffix", "02")
                 .doRun();
     }
 
diff --git a/src/test/java/net/hostsharing/hsadminng/hs/office/usecases/UseCaseTest.java b/src/test/java/net/hostsharing/hsadminng/hs/office/usecases/UseCaseTest.java
index 1570039b..7f4541ac 100644
--- a/src/test/java/net/hostsharing/hsadminng/hs/office/usecases/UseCaseTest.java
+++ b/src/test/java/net/hostsharing/hsadminng/hs/office/usecases/UseCaseTest.java
@@ -9,6 +9,7 @@ import net.hostsharing.hsadminng.rbac.context.ContextBasedTest;
 import net.hostsharing.hsadminng.rbac.test.JpaAttempt;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Order;
 import org.junit.jupiter.api.TestInfo;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.web.server.LocalServerPort;
@@ -67,7 +68,8 @@ public abstract class UseCaseTest extends ContextBasedTest {
         );
 
         final var testMethodName = testInfo.getTestMethod().map(Method::getName).orElseThrow();
-        markdownFile = new PrintWriter(new FileWriter(testMethodName + ".md"));
+        final var testMethodOrder =  testInfo.getTestMethod().map(m -> m.getAnnotation(Order.class).value()).orElseThrow();
+        markdownFile = new PrintWriter(new FileWriter( testMethodOrder + "-" + testMethodName + ".md"));
         log("## Testcase " + testMethodName.replaceAll("([a-z])([A-Z]+)", "$1 $2"));
         currentTestInfo = testInfo; // FIXME: remove?
     }
diff --git a/src/test/java/net/hostsharing/hsadminng/hs/office/usecases/debitor/CreateExternalDebitorForPartner.java b/src/test/java/net/hostsharing/hsadminng/hs/office/usecases/debitor/CreateExternalDebitorForPartner.java
new file mode 100644
index 00000000..a611cdf8
--- /dev/null
+++ b/src/test/java/net/hostsharing/hsadminng/hs/office/usecases/debitor/CreateExternalDebitorForPartner.java
@@ -0,0 +1,57 @@
+package net.hostsharing.hsadminng.hs.office.usecases.debitor;
+
+import net.hostsharing.hsadminng.hs.office.usecases.UseCase;
+import net.hostsharing.hsadminng.hs.office.usecases.UseCaseTest;
+import net.hostsharing.hsadminng.hs.office.usecases.person.CreatePerson;
+
+import static io.restassured.http.ContentType.JSON;
+import static org.springframework.http.HttpStatus.CREATED;
+
+public class CreateExternalDebitorForPartner extends UseCase<CreateExternalDebitorForPartner> {
+
+    public CreateExternalDebitorForPartner(final UseCaseTest testSuite, final String resultAlias) {
+        super(testSuite, resultAlias);
+
+        requires("Person: Test AG");
+        requires("Person: Billing GmbH", alias -> new CreatePerson(testSuite, alias)
+                .given("personType", "LEGAL_PERSON")
+                .given("tradeName", "Billing GmbH")
+        );
+    }
+
+    @Override
+    protected HttpResponse run() {
+
+        keep("Contact: Billing GmbH - Test AG billing", () ->
+                httpPost("/api/hs/office/contacts", usingJsonBody("""
+                        {
+                            "caption": "Billing GmbH, billing for Test AG",
+                            "emailAddresses": {
+                                "main": "test-ag@billing-GmbH.example.com"
+                            }
+                        }
+                        """))
+                        .expecting(CREATED).expecting(JSON)
+        );
+
+        return httpPost("/api/hs/office/debitors", usingJsonBody("""
+                {
+                    "debitorRel": {
+                        "type": "DEBITOR", // FIXME: should be defaulted to DEBITOR
+                        "anchorUuid": ${partnerPersonUuid},
+                        "holderUuid": ${Person: Billing GmbH},
+                        "contactUuid": ${Contact: Billing GmbH - Test AG billing}
+                     },
+                    "debitorNumberSuffix": ${debitorNumberSuffix},
+                    "billable": ${billable},
+                    "vatId": ${vatId},
+                    "vatCountryCode": ${vatCountryCode},
+                    "vatBusiness": ${vatBusiness},
+                    "vatReverseCharge": ${vatReverseCharge},
+                    "refundBankAccountUuid": ${BankAccount: Test AG - refund bank account},
+                    "defaultPrefix": ${defaultPrefix}
+                }
+                """))
+                .expecting(CREATED).expecting(JSON);
+    }
+}
diff --git a/src/test/java/net/hostsharing/hsadminng/hs/office/usecases/debitor/DeleteDebitor.java b/src/test/java/net/hostsharing/hsadminng/hs/office/usecases/debitor/DeleteDebitor.java
index c006ef77..527b23b6 100644
--- a/src/test/java/net/hostsharing/hsadminng/hs/office/usecases/debitor/DeleteDebitor.java
+++ b/src/test/java/net/hostsharing/hsadminng/hs/office/usecases/debitor/DeleteDebitor.java
@@ -19,7 +19,7 @@ public class DeleteDebitor extends UseCase<DeleteDebitor> {
                 .given("vatCountryCode", "DE")
                 .given("vatBusiness", true)
                 .given("vatReverseCharge", false)
-                .given("defaultPrefix", "tsx"));
+                .given("defaultPrefix", "tsy"));
     }
 
     @Override
diff --git a/src/test/java/net/hostsharing/hsadminng/hs/office/usecases/person/CreatePerson.java b/src/test/java/net/hostsharing/hsadminng/hs/office/usecases/person/CreatePerson.java
new file mode 100644
index 00000000..661f73b8
--- /dev/null
+++ b/src/test/java/net/hostsharing/hsadminng/hs/office/usecases/person/CreatePerson.java
@@ -0,0 +1,25 @@
+package net.hostsharing.hsadminng.hs.office.usecases.person;
+
+import io.restassured.http.ContentType;
+import net.hostsharing.hsadminng.hs.office.usecases.UseCase;
+import net.hostsharing.hsadminng.hs.office.usecases.UseCaseTest;
+import org.springframework.http.HttpStatus;
+
+public class CreatePerson extends UseCase<CreatePerson> {
+
+    public CreatePerson(final UseCaseTest testSuite, final String resultAlias) {
+        super(testSuite, resultAlias);
+    }
+
+    @Override
+    protected HttpResponse run() {
+
+        return httpPost("/api/hs/office/persons", usingJsonBody("""
+                    {
+                        "personType": ${personType},
+                        "tradeName": ${tradeName}
+                    }
+                    """))
+                    .expecting(HttpStatus.CREATED).expecting(ContentType.JSON);
+    }
+}