Because people keep responding to a dead thread: I already solved this a long time ago. Put HDD in a standard external case (USB), SSD goes in a special case (OWC Envoy worked for me). Connect both to the recovery rig, then find the appropriate recovery software that is able to mount and "combine" the 2 disks automagically. I don't recall the exact software that I used since it's been a couple of years.