The old "Blue" cards work in most "multicam" receivers (darkboxes, manhattens etc), These multicam receivers also also allow the viewing of the premium channels - Sky Sports and Sky Movies - which are not viewable if you use your sky card in another (ie not the receiver the card is paired to) sky receiver.
Currently the new white sky cards work in the multicam receiver - for the 6 entertainment mixes only.
They do not allow the viewing of SPorts or Movie channels...at the moment.
It will be a case of waiting for some clever greek to provide the relevant software for these multicam recivers and then upgrade the software in the receiver. This may take some time....reports are that NDS3 (the new cards encryption) has been used in SKy Itailia receiver for the last year or so and so far after 12 months noone has been able to produce new software fo multicams....