Z3 Radio Code

This is a common Problem I know... sorry! I recently bought a 2001 Z3 with "Code Wait" message on the radio. Reading through the other posts on this topic I've learned how to clear that, but when I tried the code that was on the card with the car, it didn't work. So I pulled the radio from the console to verify the s/n and learned that it's apperently not original to the car (s/n didn't match the card). So I went to my local BMW dealer and they gave me a code for the REAL radio s/n... but it didn't work either. Is there anyone on here that can help? Any other avenues?

radio is a Blaupunkt "Business CD"
S/N 29974060
The code they gave me is 43113 (that doesn't work)

Any help would be greatly appreciatted!
Thanks
Tom