Edit: sorry, I didn't notice that you already posted the software version, and that should be OK - I'll leave the next paragraph here for reference to other readers, though... Please, skip to the next point 🙂
AFAIK it depends on the software version of the television. You can check it with menu-0-0-go if you have a Beo 4 (dunno how to do that with other remotes) or simply take a look at the type sticker in the rear. If it says "SW 3.1", the picture command will not operate the stand, not with any remote. If it's 1.something, it should work. There are two different manuals for the MX6000/7000 - the first one talks about Beolink 1000 and the later one about Beo 4.
Furthermore, go to the setup menu of your tv. Do you see "stand" as the last selection down under "sockets"? If not, the TV and the stand are not communicating.
I have a MX6000 sw 3.1, a Beolink 1000, a BL7000 and a Beo 4, and the only one of those that is able to rotate the stand is the Beo 4...
Regarding the stands - if you can plug it in, it should work. MX8000 (and MX4002, I think) had a different stand, but the plug is also different.