diff --git a/cli/src/main/resources/js/functions.js b/cli/src/main/resources/js/functions.js
index 94dafa3..86390b0 100644
--- a/cli/src/main/resources/js/functions.js
+++ b/cli/src/main/resources/js/functions.js
@@ -2,6 +2,9 @@ importClass(java.util.ArrayList);
 importClass(java.util.HashMap);
 
 function hsaParseParam(val) {
+	if (val === null) {
+		return val;
+	}
 	if (val instanceof java.util.List) {
 		return val;
 	}
@@ -36,12 +39,14 @@ function hsaParseParamObject(o) {
 	var hsh = new HashMap();
 	for (var key in o) {
 		var val = o[key];
-		if (typeof val === 'object' && val.constructor === Array) { 
-			val = hsaParseParamArray(val); 
+		if (!val === null) {
+			if (typeof val === 'object' && val.constructor === Array) { 
+				val = hsaParseParamArray(val); 
+			}
+			else if (typeof val === 'object') { 
+				val = hsaParseParamObject(val); 
+			}; 
 		}
-		else if (typeof val === 'object') { 
-			val = hsaParseParamObject(val); 
-		}; 
 		hsh.put(key, val);
 	};
 	return hsh;
diff --git a/framework/src/main/java/de/hsadmin/module/impl/AbstractProperty.java b/framework/src/main/java/de/hsadmin/module/impl/AbstractProperty.java
index 1df5309..99de592 100644
--- a/framework/src/main/java/de/hsadmin/module/impl/AbstractProperty.java
+++ b/framework/src/main/java/de/hsadmin/module/impl/AbstractProperty.java
@@ -22,6 +22,7 @@ public abstract class AbstractProperty<T> implements Property<T> {
 	
 	private PersistentObjectMapper<T> persistentObjectMapper;
 	private ParameterMapMapper<T> parameterMapMapper;
+	private boolean undefinedValue;
 
 	public AbstractProperty(
 			final ValueObject owner, 
@@ -34,6 +35,7 @@ public abstract class AbstractProperty<T> implements Property<T> {
 		this.policy = readWritePolicy;
 		this.search = searchPolicy;
 		this.required = required;
+		this.undefinedValue = true;
 	}
 	
 	protected PersistentObjectMapper<T> getPersistentObjectMapper() {
@@ -50,7 +52,7 @@ public abstract class AbstractProperty<T> implements Property<T> {
 	}
 
 	@SuppressWarnings("unchecked")
-	protected void setParameterMapMapper(ParameterMapMapper<?> mapper) {
+	protected void setParameterMapMapper(final ParameterMapMapper<?> mapper) {
 		parameterMapMapper = (ParameterMapMapper<T>) mapper;
 	}
 	
@@ -74,6 +76,11 @@ public abstract class AbstractProperty<T> implements Property<T> {
 		return required;
 	}
 	
+	@Override
+	public boolean isUndefined() {
+		return undefinedValue;
+	}
+	
 	@SuppressWarnings("unchecked")
 	public Class<? extends Property<T>> getPropertyType() {
 		return (Class<? extends Property<T>>) getClass();
@@ -82,11 +89,15 @@ public abstract class AbstractProperty<T> implements Property<T> {
 	@SuppressWarnings("unchecked")
 	@Override
 	public T getValue() throws TechnicalException {
+		if (undefinedValue) {
+			throw new TechnicalException("undefined value");
+		}
 		return (T) ReflectionUtil.invokeGetter(owningVO, getName());
 	}
 
 	@Override
 	public void setValue(T value) throws TechnicalException {
+		undefinedValue = false;
 		ReflectionUtil.invokeSetter(owningVO, getName(), value);
 	}
 
@@ -115,9 +126,8 @@ public abstract class AbstractProperty<T> implements Property<T> {
 
 	@Override
 	public void copyValueToPersistentObject(Object persistentObject) throws TechnicalException, UserException {
-		T newValue = getValue();
-		if (newValue != null) {
-			getPersistentObjectMapper().writeValueToPersistentObject(persistentObject, getName(), newValue);
+		if (!undefinedValue) {
+			getPersistentObjectMapper().writeValueToPersistentObject(persistentObject, getName(), getValue());
 		}
 	}
 
diff --git a/framework/src/main/java/de/hsadmin/module/property/Property.java b/framework/src/main/java/de/hsadmin/module/property/Property.java
index ac99264..6e28d6a 100644
--- a/framework/src/main/java/de/hsadmin/module/property/Property.java
+++ b/framework/src/main/java/de/hsadmin/module/property/Property.java
@@ -25,6 +25,8 @@ public interface Property<T> {
 
 	public boolean valueIsNullOrEmpty();
 	
+	public boolean isUndefined();
+	
 	public void copyValueFromPersistentObject(final Object persistentObject) throws TechnicalException, UserException; 
 	
 	public void copyValueToPersistentObject(final Object persistentObject) throws TechnicalException, UserException;
diff --git a/framework/src/main/java/de/hsadmin/module/property/StringSetProperty.java b/framework/src/main/java/de/hsadmin/module/property/StringSetProperty.java
index b638272..a393a14 100644
--- a/framework/src/main/java/de/hsadmin/module/property/StringSetProperty.java
+++ b/framework/src/main/java/de/hsadmin/module/property/StringSetProperty.java
@@ -1,7 +1,6 @@
 package de.hsadmin.module.property;
 
 import de.hsadmin.common.error.TechnicalException;
-import de.hsadmin.common.error.UserException;
 import de.hsadmin.common.util.ReflectionUtil;
 import de.hsadmin.module.ValueObject;
 import de.hsadmin.module.impl.AbstractProperty;
@@ -67,18 +66,4 @@ public class StringSetProperty extends AbstractProperty<StringSet> {
 		}
 	}
 	
-	@Override
-	public void copyValueFromPersistentObject(Object persistentObject)
-			throws TechnicalException, UserException {
-		// TODO Auto-generated method stub
-		super.copyValueFromPersistentObject(persistentObject);
-	}
-	
-	@Override
-	public void copyValueToPersistentObject(Object persistentObject)
-			throws TechnicalException, UserException {
-		// TODO Auto-generated method stub
-		super.copyValueToPersistentObject(persistentObject);
-	}
-	
 }
diff --git a/services/src/main/java/de/hsadmin/service/pac/PacService.java b/services/src/main/java/de/hsadmin/service/pac/PacService.java
index 9c32ec9..7facc4f 100644
--- a/services/src/main/java/de/hsadmin/service/pac/PacService.java
+++ b/services/src/main/java/de/hsadmin/service/pac/PacService.java
@@ -44,12 +44,16 @@ public class PacService extends AbstractModule<PacVO> implements PacServiceLocal
 			throws UserException, TechnicalException {
 		final PacVO vo = super.create(requestContext, prototype);
 		final Pac bo = new Pac();
-		final String inetAddressProperty = prototype.getInetAddress();
-		assert inetAddressProperty != null;
-		bo.setCurINetAddr(findInetAddress(inetAddressProperty));
 		final String hiveProperty = prototype.getHive();
 		assert hiveProperty != null;
-		bo.setHive(findHiveByName(hiveProperty));
+		final Hive hive = findHiveByName(hiveProperty);
+		bo.setHive(hive);
+		final String inetAddressProperty = prototype.getInetAddress();
+		if (inetAddressProperty != null) {
+			bo.setCurINetAddr(findInetAddress(inetAddressProperty));
+		} else {
+			bo.setCurINetAddr(hive.getInetAddr());
+		}
 		final String basePacProperty = prototype.getBasePac();
 		assert basePacProperty != null;
 		bo.setBasePac(findBasePacByName(basePacProperty));
diff --git a/services/src/main/java/de/hsadmin/service/pac/PacVO.java b/services/src/main/java/de/hsadmin/service/pac/PacVO.java
index cf6d718..3952700 100644
--- a/services/src/main/java/de/hsadmin/service/pac/PacVO.java
+++ b/services/src/main/java/de/hsadmin/service/pac/PacVO.java
@@ -164,8 +164,12 @@ public class PacVO extends AbstractVO implements ValueObject {
 	{
 		assert persistentObject != null;
 		final List<Property<?>> properties = properties();
-		for (Property<?> p : properties) {
-			if ("pacComponents".equals(p.getName())) {
+		for (Property<?> prop : properties) {
+			final String propName = prop.getName();
+			if ("customer".equals(propName) || "basePac".equals(propName) || "hive".equals(propName) || "inetAddress".equals(propName)) {
+				continue;
+			}
+			if ("pacComponents".equals(propName)) {
 				if (persistentObject instanceof Pac) {
 					final Pac persistentPac = (Pac) persistentObject;
 					final List<PacComponentVO> pacComps = getPacComponents();
@@ -178,7 +182,7 @@ public class PacVO extends AbstractVO implements ValueObject {
 					}
 				}
 			} else { 
-				p.copyValueToPersistentObject(persistentObject);
+				prop.copyValueToPersistentObject(persistentObject);
 			}
 		}
 	}