The problem lies with the gateway. Normally, a VPN connection uses the local gateway for everything which prevents access to remote resources. You have the exact opposite problem - the client is using the remote gateway and can't reach anything local.
What you're asking about is Split-Tunneling and it's a big security hole that most admins won't entertain. While technically possible, it's really not a good idea. The point of the tunnel is to remotely attach to a network with a secure tunnel. By allowing local access too, you effectively begin routing packets from each network through your computer (which is now acting as a bridge).
