I can't see any point in bothering to retrofit the Beogram control into a 2400. It's just start, stop and pause anyway.
The
service manual on site seems to cover both 2400 and 2400-2, but after a
quick glance over it it doesn't say a word about the Beogram control.
The ultrasonic receiver and control schematic is there though. And the
Beogram 4004 service manual is rather vague on the subject too, as well
as being almost illegible.
Of course you could construct any control stuff into the Beomaster starting from your own ideas, but see paragraph 1...