Go onto the Mac Pro forum.
I have a 2010 Mac Pro (5,1) and I can unlock my mac with my original (series 0) as well as my series 4.
The bluetooth card in your mac does not support it. It requires changing out the WiFi/Bluetooth card for a more recent version that supports the necessary protocols, and doing a few terminal commands to hack support for Continuity and Handoff into the system.
It's possible.