Hi,
I dont think the ibus cable will work with Carsoft, you have to use Navcoder.
I have a 03 E39, it has (factory mounted) bluetooth ULF, i didnt have the VR, but after i bought Navcoder and saw it was "unchecked" in settings on the ULF module, i checked it, saved it, tested it and it works!
So Navcoder should be able to fix it.
I just bought a 13. gen ULF, hoping it has better sound then my 1. gen. :P
Regards
Fredrik