Virtual Number Voicemail Help

I added the free virtual number that Tim graciously provided us :)
I set up the voicemail for the number and when I call from any phone I correctly get the virtual numbers VM box.
Now... when I forward my cell phone to the virtual number something strange happens. Callers to my cell number are directed to the voicemail box of my main Voipo number.
Anyone know why this happens ? My cell is directed to my virtual number, so it should get the VM box of the VN, right ?
I had planned on getting rid of one of my other providers and just forwarding my cell to the Voipo VN, but I need the VM to go to the VN's box.

Do you have any Custom Call Routing setup for that cell number?

No Sir, I have no custom call routing setup at all. Do I need to set some up ?

Edit: I believe the CID of the caller is passed, not the CID of my cell.