You configure which SSD you want to use for SRT and how much space (up to 64GB) you want to use through the Intel RST software; it won't care how the SSD is connected.
If you want to use the same SSD for caching and for system/boot partitions, you'll have to install Windows twice to do it: first on the HDD to install RST to configure SRT (heh), then the real install to the newly configured SSD.
And, yes, you can cache a RAID.