The kernel does now have support but only basic support of raid though I’m not sure if the init has the dmraid and/or mdadm utilities.

Probably you could also capture one image using clonezilla from that particular kind of client just to have a template of clonezilla files ready. Then swap ‘sdaX.<fstype>-ptcl-img.gz.aa’ files with those you got from fog. From what I could find out they should be in the correct format (partclone packed with gzip) already. You just need to rename them properly. Give it a try…