content of /etc/chatscripts/BluetoothDialup :

TIMEOUT 35
ECHO    ON
ABORT   '\nBUSY\r'
ABORT   '\nERROR\r'
ABORT   '\nNO ANSWER\r'
ABORT   '\nNO CARRIER\r'
ABORT   '\nNO DIALTONE\r'
ABORT   '\nRINGING\r\n\r\nRINGING\r'
''      \rAT
OK      'AT+CGDCONT=2,"IP","internet"'
OK      ATD*99#
CONNECT ""

no username/pass, /etc/ppp/peers/BluetoothDialup file content in accordance with the main BluetoothDialup article.

Tested on Nokia E51. If it's not working on your phone you may try changing AT+CGDCONT=2 to AT+CGDCONT=1