VoIP application for Windows Mobile and Symbian

2 tasks total. One for Windows Mobile; other is for Symbian. Do not contact about other platforms. Would prefer same developer for both. Would only work with developer experienced in VoIP dialer implementation. Strict confidentiality required. All work designs and code will permanently become copyright of the Requester. Task revolves around bridging audio between WLAN and GSM networks. It's a hybrid of VoIP client to receive inbound calls under NAT (G711/G729. wifi only), call recorder and GSM dialer. This is open ended, long-term development project.