Very good question.
What remote are you using at the moment?
If you can control it with a Beolink 1000 then a Beo4 should be able to work.
The one thing that I'm sure about is that the VHS 91.2 is able to work with a Beolink 1000.
The sure thing is to update the Beovision to LX range and then there would be no problem.