The HBA is supposed to support both sas and sata; even if it didn't I'd assume that the backplane would....?
http://www.lsi.com/downloads/Public/...3442X_r_pb.pdf
Here's a comparison with the Adaptec
http://www.adaptec.com/nr/rdonlyres/...8300lsi_13.pdf
Out of interest to anyone that owns a 520; is the backplane SAS Cable connected straight to the Motherboard?
Whenever an old snap 4x00 comes to me with boot issues the first thing I do is pull out the SCSI HBA and in many many cases that move allows the Snap to boot properly....