umd gen v4.00

Hi 2 all, err... I've 2 hard drives(primary nd secondary) my primary HD is only a 20gig, has abt 500MB left nd my 2nd is a 160gig with about 1.27gigs. I just want 2 know where the UMD GEN v4.00 stores its temp files nd if there is a way of changing it so that it uses my 2nd hard drive as my primary only has abt 500Mb (which isn't much as the umd gen needs about 1.35gigs worth of free space)