Microsoft Server 2008 VPN advertise multiple networks?

I have about a dozen different sites with over a dozen different subnets, all routing fine. To make it simple Ill just refer to areas A, B, and C. A being a branch office, B being our headquarters and C being another branch office. When I have a client connect to the VPN server in area B they cannot ping area A or C. How can I get the client to ping all locations without using the Use remote networks gateway? Can I force the VPN server to advertise networks in other areas?
Our site B includes a Primary domain controller (server 2008), a Cisco ASA 5510 and a VPN server (server 2008. The network is running a 10.50.0.0\19 subnet.
Site A has a Secondary Domain controller (server 2008), a Cisco ASA 5510 (soon to be replaced with sonicwall). The network is running a 172.16.0.0\22 subnet.
Site C has a Secondary Domain Controller and a simple router. The network runs a 192.168.1.0\24 subnet.

The client runs (for testing) Windows 7 and gets a 10.50.3.104 address. The DHCP server at site B assigns this address. When I try to connect to the internet or any other address not on site B I am not able to connect. However when I disable the use remote network default gateway I connect fine until needing to get to site A or B. when I try to ping 172.16.1.225 (a printer on site A) I get nothing, when I tracert it I see the traffic going to the internet instead on the site B router.

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