Hi domrom
You try to mix two generations of Beolink: Your Beocenter works together with the MCL 82 Link-System and the Terminal Controller or the master control 7700 Remote controls. The MCL2A's are one generation later. They work together with the newer remote controls like beolink 100 or beo4.
The wiring you installed is OK, its the same for both systems.
So you have three possibilities
1. switch to a newer beocenter / beosystem like the beocenter 9500 or the beosystem 4500 (But not to a musiccenter with masterlink)
2. Change the MCL2A's to MCL-82
3. Buy a converter (There was such a system on the market, but its rare)
I highly recommend you the first or the second solution (Had the same problem with my beomaster 3000 which is only compatible with the beolink 30. I bought one of these converters but never succeeded in bringing the system to work.
Good luck
David