[cisco-voip] Cisco Router to Call Manager 3.3

[Heriyadi Setiono]

Dear Cisco-ers,

In my company would like to develope VoIP connection through WAN to call Mgr 3.3. 
The design would be 

PSTN -> to FXO Card remote site router 2621 --> VoIP WAN Cloud with Codec G729br8 -> CM as a MGCP gateway (codec g711).

Is it possible doing this design ? or may be other can help me alternate solution. 
we're going to reroute remote PSTN line to Call Center Head office so the customer at remote site can still use local rate.

Best Regards,
Heriyadi