How do I upload a program with xBee wirelessly?

Hello! I have been stuck on this problem far too long now, and would love any and all help I can get.

How do I wirelessly program an mega with the xBee shield?

Communication between the two xBees works fine (I can turn an LED on/off), but I can't upload a sketch to the mega wirelessly through the xBee.

Thank you.

There is more involved than just tx/rx/ground. Have you sorted that out?

I am using the xbee shield from sparkfun.