Convert Audi CAN to VW CAN Signal

Hello can tool,

I've been looking for a CAN converter for quite some time now, if such a thing even exists.

I'm planning to install a specific Volkswagen radio in my Audi Allroad C5 (year 2004) which has a CANBUS system. However, it seems the protocols are not compatible because the Volkswagen radio isn't turning on.
Basically, it works, I can turn it on with an ON/OFF button, but then not all of the functions are available.

Is it possible to find or create a converter that would allow me to use a VW CAN bus with my Audi system? There's very little information available about the CAN bus in the Allroad; essentially, it only handles things like infotainment, lights (which even turn on via the radio), and ignition.

Perhaps you can help me. Oh, and one more thing about why I want to install a VW radio: maybe people shouldn't worry too much about the meaning or purpose behind it.

Thank you very much and best regards.