If the BS9000 did not even react to option setting commands and the receiver is clean, the ir receiver might be faulty. But first I would check the Beo4 with another Beosystem. Maybe there is a Beoworlder in Greece who will test it for you? You could send it to me, but it`s a bit far I`m afraid... Another option can be to buy a (very cheap) BL1000 and test your BS9000. If the IR receiver is faulty and it can not be repaired there might be a workaround with a Beolink active.
You can connect a BL active with ir receiver via Masterlink to your BS and connect the BL8000s to the BL active. Now you can control the BS9000 with a Beoremote through the BL active.
Stefan