Metasploit Framework

From what I can tell, I have come across some vulnerable HPUX systems that are running a vulnerable tivoli storage manager client. It appears as though the exploit is successful, but I'm unable to attach a payload of a unix flavor because the exploit is currently listed in the windows branch. I'd like to either see if there is a way to override the "not a compatible payload" error to fully test this or if it might be possible to see if the exploit does actually work on non-windows systems, and get it classified a bit differently. Please accept my apologies if this is simply my own ignorance. I did google a bit to try and find answers on my own.