palm pre and google voice?

I posted this on Precentral but nobody was able to help... lol, so I thought I would try asking the question here

I am trying to set up call forwarding to google voice on my pre, I entered the *28 + the number google gave me.. but when I do that, it says "the feature code you've entered is not valid"

I tried the same thing on my sprint blackberry tour and it worked flawlessly.
Am I doing anything wrong?

You could try using the GV app for the Pre.

No I'm trying to set up calling forwarding on the Pre, so when a call is unanswered or ignored, it would forward the call to my google voicemail mailbox

Oh... Hmm... Ask Sprint about that.

They were no help... Got put on hold for 15 minutes and they were not able to come up with a solution