doubts in Illustra

I am using a Illustra(research copy) for a study. I have been having a truly frustrating experience writing C functions. I would greatly appreciate it if someone could answer these questions 1) Can a C function return a Set of composite types in illustra ? 2) Can a aggregate C function return a Set ? Even the simplest code for the above cases gives me a internal error with no further feedback. Thanks, Srinivasan Udayakumar (Uday) Graduate Student, Ohio State University