When I first got my car the boot pop would work with the rest of the car still locked
This has since been changed to only be able to pop boot when the car is unlocked
So on yours it might not be programmed at all but should be doable
Find a good Indy or ask on hear if anyone in your area would be willing to do some coding for beer tokens
Have a look at this :-http://www.programyourkeys.com/BMW_Z4_Key_Remote_Control_Fob_Programming.html
used this a few weeks ago when I got my new key from BMW