The onboard one as the combo-card is not supported by MorphOS (and probraly will never be).

O.k. I could have put the boot.img and maybe an ISO-file of the MorphOS-CD to claim some level of booting from SATA ...

AFAIK there is only one out of the box Mac and MorphOS (2.8) compatible outthere (made by Sonnet and hard to find).

Cheap PC cards with the right chip should work (once you found a way to load boot.img from another device) and some of those might even be reflashed to work directly.

Just wait for 2.8 and see what the otions are...