VirtualBox Windows 7 VM with Matrox DualHead2Go

[HKM]

Hi All:
I'm using a 2012 MBP with a DualHead2Go. I run a VirtualBox VM with guest OS Windows 7. I need a way to 'trick' my VM into a different resolution. In the alternative, I want to set a manual resolution for my Windows VM, to confine it to one of my monitors. Specifically, I don't want my Windows VM to span both of my external monitors.

Any thoughts?

[mpack]

Have you installed the Guest Additions inside the guest? If not then see the user manual, section 4.2.

[HKM]

Yes, I have.