If your generating SOAP proxies using Apache Axis/2 you may find yourself hitting strange errors.. Whats even stranger is that you can generate proxies using JDeveloper and it works fine in tooling like SOAPUI.. Well help is at hand..
The most common error is
IWAB0399E Error in generating Java from WSDL:
java.lang.RuntimeException: Unknown element _value
I'm not sure if this is a bug in Fusion Sales Clouds base tech (ADFBC SDOs) or a bug in Apache Axis but there is a workaround and engineering are looking into this.
For a workaround you have two options
e.g. xjs -wsdl http://<salescloudsoapendpoint/opptyMgmtOpportunities/OpportunityService?WSDL
Enjoy and let me know if this works for you :-)