AT Command Software to send USSD codes and SIM Toolkit commands - repost

Task: Need to send a GSM command string ( USSD or SIM Tool Kit commands ) to request a pre-paid mobile credit send, credit recall, and balance check. These commands will be triggered by a web server, and communicate with the web server and log all events. Options: - Create stand alone software that will communicate with the web server. - Use the Diafaan software or similar, and customize with it’s C++ / .Net scripting connector - Use other pre existing software Current Hardware: Windows Machine with remote access 8 Port modem bank, 1 port Wavecom modem 3 SIM cards from Local providers