diff --git a/src/main/java/de/jalin/ldapadmin/hsadmin/MailboxDAO.java b/src/main/java/de/jalin/ldapadmin/hsadmin/MailboxDAO.java
index 01c312a..c06de32 100644
--- a/src/main/java/de/jalin/ldapadmin/hsadmin/MailboxDAO.java
+++ b/src/main/java/de/jalin/ldapadmin/hsadmin/MailboxDAO.java
@@ -45,12 +45,14 @@ public class MailboxDAO {
 	}
 
 	private String getMailbox(String pac, String localpart) throws IOException, XmlRpcException, MailboxNotFound {
+		final String mailboxPostfix = localpart.replace('-', '_');
+		final String mailboxIdentifier = pac + "-" + mailboxPostfix;
 		final List<Serializable> xmlRpcParamsList = new ArrayList<Serializable>();
 		xmlRpcParamsList.add(pac);
 		xmlRpcParamsList.add(ticketBox.getTicket());	
 		final HashMap<String, Serializable> whereParamsMap = new HashMap<String, Serializable>();
 		xmlRpcParamsList.add(whereParamsMap);
-		whereParamsMap.put("name", pac + "-" + localpart);
+		whereParamsMap.put("name", mailboxIdentifier);
 		final Object[] rpcResult = (Object[])rpcClient.execute("user.search", xmlRpcParamsList);
 		if (rpcResult.length == 1) {
 			@SuppressWarnings("unchecked")