Haldex Control

Hi all.

Has anyone on here managed to control a Haldex rear 'diff' (Audi , VW etc) using the PDM Can output?

I have an Audi TT (early - 8N) and looking for the best way to control the diff. I know there are a lot of controllers out there so I'm wondering if the CAN 'codes' are in the public domain? Thanks in advance.