The card I ordered has got 2 chips on it, so only 2 of the 4 sata ports worked.
I suspect only the working chip is a Marvell 88SE9215
Ive ordered the card (above) thats confirmed to work with Xpenology, it only has 1 chip (Marvell 88SE9215) which drives all 4 sata connections.
I'll let you know what happens when it arrives.
Mike