Pairing in nokia + ericsson + siemens - serial port

hi guys,

i have something i dont understand here.

I have a bluetooth serial port which i would like to access through an
application im going to do myself.

BUT every time i get one of the phones trying to connect to it, after
authorization - it tells me that "the unit you are connecting to
doesnt support handset / hands free".

Well, ofcourse it dont !

Is it possible to connect to a unit, without the phones are trying to
identify the type of the hardware ?

And is it possible for me, via the SDK's - to access this unit, and
write code that talks through the interface, even though the phone
doesnt understand it ?

I might have missed something, it could be that firmware upgrades are
needed, so the phone can understand BT serial ports ?

My bluetooth knowledge is small - so i maybe dont even have the
principles right here ?

Someone here who is able to explain me whats going on in the phone -
and if it demands a driver for each BT interface or what ?

OR is it something you get from a thirdpart ?

really hope you can help, thanks alot