Inability to describe ResultSets returned by ProcedureQuery causes all kinds of issues. E.g. see this thread (Long vs Integer):
The fix for now is to allow setting result set column descriptors at the procedure query level (without Modeler support). This is how far we will go in 1.2...
Check out 1.1.3 fix of this issue here: http://objectstyle.org/confluence/download/attachments/134/cayenne-1.1.3p1.jar?version=1