I have been having issues with rnav approaches, ill select an rnav runway and a transition, and while plugging the discontinuity, my alts will alter for a descent and when i activate they all go back to my cruise alt, if i try to manually add alts, the fmc or autopilot refuses to make a t/d  point for me.  However when I use an ILS approach with a STAR and a transition my automatically altered altitudes remain intact and I get a T/D point.  Am i doing something wrong for RNAV?  I really like this plane and want it to work, so if I'm doing something wrong I'd like to know before i uninstall it and save myself the headache.  Before anyone asks I'm runnin latest FSUIPC, I have tried reinstalling the 767 AND I have reinstalled FSUIPC after adding another aircraft.