Help - I can only get one key to work at a time

[AudiBMWSX45]

Both of my keys start up the car, but I can only get one of the transmitters to work at a time in terms of the unlock / lock functions.

I'm following these instructions to program both keys:

http://www.xoutpost.com/articles/x5/e...ob-bmw-x5.html

However, if I insert Key A into the ignition first, Key B won't work. If I insert Key B first, Key A won't work.

Any thoughts?

Thanks.