I'm guessing you only need a few applications to be in your VNC session for your presentation. The easy way around without using teamview is to VNC into your backtrack computer locally, start the applications you needed "shared", then when you VNC from the remote windows workstation, the things you needed will be there.
To VNC into your backtrack machine locally I like to use
Then start whatever you need.
I also always create a tunnel to my localhost and VNC in through the tunnel, when using a VNC screen from a remote VNC server. VNC passwords are transmitted across the wire in clear test like telnet and FTP. The tunnel protects your credentials and session.
When connecting in windows using VNC you connect to
c:\ssh -L 5901:127.0.0.1:5901 email@example.com