Like Fuscus said, i would bump the cage temps up for a day (have noticed that the slight increase in temps get my pythons agro), then that night i would go to the cage in the dark without disturbing your python, get some long tweezers ( or you can get these long bending things from a place like cheap as chips in the tools section, when you press the end this little clamp thing comes out and grabs whatever you are grabbing, and they are like $2, i think they are a car tool, ill post a pic if needed im crappy at explaining), anyway, grab the mouse and wiggle it in fromt of you python, if it still doesnt have a go, lightly bump it about an inch or so behind its head, mine usually turn round and grab the mouse. Some let go after coliling round, if they do this, get the python to coil around it again, this time keep a hold of the mouse and keep wiggling for a few seconds then let go. If it fails again, just try again at least a week later. Dont feed live in the process though, it will undo all your hardwork. remember they can go ages without a feed. maybe after 4 weeks of no success give a live just to keep it going if you are worried and try feeding thawed again the next 4 weeks.remember after you have bumped the teps for that day, return temperatures to normal.
Oh yeah, have you tried feeding a thawed one after a live one? Sometimes they take a frozen thawed one straight after a live one.
hope i helped.
cheers
Mark