I know this thread is a bit old but I thought any one else having this problem can refer to my web page here.
I had a lot of problems at first working this one out. So I made a program to create the bluetooth com port.
1. Download and install the program sjdsoftbt-tool from my website http://www.sjdsoft.hk/Linux/BluetoothModem/index.html
or directly here *sjdsoftbt-tool*
It was made in gambas 2.0 but it should install the required dependencies automaticly .
2. Follow the instruction on my How to Guide
this covers most phones and there pit falls and problems you can have.
Enjoy, and please do report any bugs.