You should be able to boot from the sata controller, i have done it before but this was on a board with an onboard secondary sata controller and i'm not sure how exactly it works, and how or if the bios of the board and the bios of the controller communicate. I believe that sata drives are emulated as ide drives in some way to appear in the main bios as an ide drive, this seems to happen on modern boards with integrated sata but i'm not sure if the drives would appear in the bios as ide drives or what.
I'll be finding a few of these things out soon as i'm adding sata drives and a controller to a board without native sata support, so if someone else can't clarify how it works i'll probably end up finding out.
Are you sure its worth sata functionality bearing in mind it offers no real speed improvements and it tends to cost slightly more for a sata drive?
Having said that there are performance improvements with native command queuing but i'm not sure if they are significant enough to warrant the cost of a sata controller and the premium for a sata drive.