To review:
I am running the chipset in RAID mode (look at the picture above from Device Manager). The board is built with the Intel Z97 chipset. I have a Intel 4790k processor.
I am using the Intel SATA ports for RAID1 using the Seagate SSHD drives and booting off of the RAID1 drives. Working fine. However, they are showing as stadard drives and there is no indication that the RST system is aware they are SSHD drives (i.e. to share hint information). By reading http://www.seagate.com/about-seagate/news/seagate-intel-developer-forum-2012-master-pr/, I would have thought that the Intel chipset would recognize the Seagate SSHDs, but I can live with that.
The real problem I am trying to solve is the use of the Plextor PCIe SSD connected to the M.2 port as an SRT cache. Reading http://www.intel.com/content/dam/www/public/us/en/documents/technology-briefs/smart-response-technology-brief.pdf, that should work fine. RST does not see the PCIe SSD. By definition, a PCIe SSD can not connect to an Intel SATA port. If http://www.intel.com/content/dam/www/public/us/en/documents/technology-briefs/smart-response-technology-brief.pdf, is to be believed, I should have no issue.