I have a IPxOffice with a PRI and I can have setup private libraries and flexicall for a couple of extensions to ring their Verizon cell phones, and this works the problem is we want the calls to go to the cell phone's voicemail rather than back to the Coral Message Center.

I have St.t Flexicall N/A set out to 450 and the Call Fwd N/A removed from the extension but after ringing the cell phone for several seconds the call continues to ring at the Extension and stops ringing the cell phone or going to the cell phones voicemail.

Any thoughts?

Ya, if you aren't using the Flexicall features simply call forward all to the cell.

That was my backup plan.

Check for your CF/NA EXT setting too. Also see if that phone is in some sort of Boss group as well.