With sony ericcson phones, it's the serial port profile. The DUN profile is seperate, and I assume different. What I don't know is if you can be connected to the SPP while the phone is connected to the car kit. I know with my Samsung A900, you can't connect to the serial port while it's connected to a car kit.

The easier solution is to just buy a parrot CK3100, which come with a nice screen you can use for caller ID and going through your phone book. Not as elegant, but unless you're going to get the empeg to impliment the HFL profile completely, it's probably a better solution.

Matthew