It is not an uncommon occurrence to run into problems when trying to discover a WSDL using the Web Service Integration component from within the Process Designer tooling. These scenarios can happen for a variety of reasons, ranging from the wrong URL being used to actual problems in the structure of the WSDL or associated XSD files. The problem is that from Process Designer, the only error reported is a pop up box that looks like this:
This error does not help too much to point out the actual core problem. All is not lost, though. While Process Designer currently does not give a detailed message, Process Center does. It should be noted that when doing the WSDL discovery, it is actually done from the Process Center side. So even though you are using Process Designer, it is the connected Process Center that has the actual detailed log files. If you experience a problem with WSDL discovery, the best place to check is the SystemOut.log file, which is located in the Process Center's profile logs directory. In most cases, the resulting error will directly point to the problem and it can be remedied.