I need help with RDP and dual monitors on Win7 machine?

I use dual monitors on my vista machine. This works great so i can RDP to my work desktop. And it spans. However when I use my Win7 machine (home edition) it wont span. I have changed my display to be the same resolution on both monitors, I have changed it under options and that didnt work. I use mstsc.exe /span. I have extend my desktop and that didnt work.

What am I missing?