Virtual server & Vista

I have a desktop PC running XP Pro with with Virtual server 2005 R2 running
Windows server 2003 and windows sharepoint services. The network adaptor of
the VM is configured to the external ethernet adaptor of the host using a
static ip address 192.168.0.200 and the gateway is the router 192.168.0.1.
This set up works perfectly and I can access the sharepoint site on the VM
from the browser on the host and the VM shows up as part of the MSHOME
workgroup. My problem is trying to replicate this om my laptop running vista.
Although I need this to work without being connected to a wider network, the
Vm on the vista can ping the router and the desktop on the network if
connected but it cannot see it's own host (the laprop). Any suggestions?