Because your X5 is a 2004 with Assist, there is no functional Bluetooth feature/section in that TCU module. However, BMW enabled the full OEM use and functionality of a CPT9000/Motorola V60 with that TCU module for that year.

That's the purpose of that CPT9000/V60 cradle, to plug that phone in there and be controlled by the TCU, display information in the Nav screen and use the steering wheel phone button. That's what I did with my 2004 M3 with Assist: http://forum.e46fanatics.com/showthread.php?t=192232

Your best option is to get an OEM ULF module and replace the Assist TCU. If you want to keep the Assist service a new TCU (MY2005+, the newer the better) will be required.