Some time ago I managed to move Win7 to mSATA SSD drive.
As I posted before to do this I pulled off HDD drive to make mSATA SSD drive the only one in the system.
After that installation goes as ussual.
When you get finished with installation and put HDD back, make sure you have mSATA card drive placed above the HDD in BIOS boot list.
Some benchmarks of my a bit outdated Samsung 128GB mSATA SSD drive:
blank disk, before installation of Win7 and other soft
Samsung mSATA SSD 128GB test
and this benchmark was made with 70% full disk:
Samsung mSATA SSD 128GB test on full disk
cmexonat's blog 