Installation Stand-up heating – supply via diesel return line

Hello together, I am currently expanding my second camper. This time, however, not with gas heating, but with a diesel floor heating. Many go over the tanker and expand the whole tank. That would be my alternative now, but I would prefer to implement the supply of the heating via the fuel return line. Unfortunately, in the construction guidelines I can’t see where this is located, over the pictures of the spare part it is a bit easier. 1. Is it possible that a friendly forum friend with BEMM will give me access to the certainty of where the line is located 2. Does someone have experience of tapping the return line?