As you all know by now that simple things can get complicated with JDeveloper. This is one of them,
While working with BPM you sometime need to alter the Payload type and add new attributes to it. In able make those new attributes visible at the ADF taskflow side you need to refresh the data control definitions. This is a very simple, straighforward task.
The issue comes around when you work with a team , where each member uses a different folder structure for their dev box.
The project that you have the ADF pages and taskflows keeps a reference to the payload's schema definition files. The problem is this reference uses an absolute path instead of a relative path. So once you move your workspace to a different folder you can no longer do a "Refresh Data Control". To workaround this open DataControls.dcx file and update the references to the PayLoad XSD files.