NTLM 2 auth in 4.5.1

After installing 4.5.1 I can no longer access a Microsoft Navision web service with NTLM 2 authentication.

I get the following error:
Error loading ["Web service URL"]: org.apache.xmlbeans.XmlException: org.apache.xmlbeans.XmlException: error: Unexpected end of file after null

It works fine in 4.5.0.