Asterisk with FreePBX and Huawei USB dongles

Hi, The goal is to establish an asterisk server and freepbx for the purpose of voip termination in GSM network. The freelancer has to do the following: - Install asterisk server and configure it to operate with Huawei usb dongles (modems) having prepaid simcards to connect to the GSM network. - Be able to attach more huawei usb modems to the server if needed. USB hubs will be used to attach the usb modems. - The server shall be able to terminate voip calls comming in codecs g729 and g723. - Other standards codecs like G722, G726, alow, ulow... shall be supported - Send ussd and ivr to each sim card to topup and credit check. - Display how much credit is available in each sim card. - be able to listen to the channels if they are busy. - If a channel is busy the call shall try automatically the next channel and so on till it finds a free channel. - FreePBX shall be used to monitor and configure the system You are free to specify which distribution and version of FreePBX and Asterisk to be used. You shall define which model of Huawei usb modems have to be used with asterisk (compatible with Linux and asterisk) Thank you, Best regards