Changing the routing behavior could be a simple matter.
If you are using a connection that was manually created on your computer via the 'Add new connection' wizard, simply open your networking and dialup connections folder. Right click on the VPN connection and select properties. Click the networking tab, then click on TCP/IP to highlight it. Click on the properties button, then the advanced button. The general tab should be on top, and the only option on that page is 'Use default gateway on remote network'. Unmark that box and you should be good to go.
If your connection was created with the CMAK, you will not have this option. If you were given an .exe file to install the connection on your computer, this would be the case. It is a fairly simple matter for whoever built the connectoin to change it for you, but some admins use this option because it gives them a (false) sense of added security, so they may not be willing to do so.