EM7305 setting APN Username and Password

for a custom application our task is to define a dynamically PDP context while starting windows.
There is no problem to set the APN Name per AT Command, but I found no solution for setting an APN username and password.

The goal is to set these parameters with a small c++ prog.

OS is Windows 7 64bit

Any hints how to set the username/password ?


What about CGXCONT ???