Here is a small app from me and Roach2010 which allow you to enable the 3G settings menu after that you flash a rom or the 3g enabler from the CWM.
This app need root permissions and overwrites the bootloader, so it may cause some problems. If you get a problem, just use nvlash.
- Me for programming this app
- Roach2010 for his bright idea and for having provided the modded bootloaders
If you have any issue, please report it. Thanks