My WSDL works and from the process playback in Workbench I can tell that it is being called actively.
However, there is a small problem.
In any event, for practical purposes, it works, but I would like to find out how to transfer variables.
This is stored on the Object menu of the relevant field in Import/Export Bindings (Execute WSDL):
It can be best seen by opening the xdp of the document in the xml editor of your choice, where it will appear as something like;
<connect connection="GeProcessList" usage="importOnly" ref="!connectionData.GetProcesList.Body.invokeResponse.errorCode"/>