Problem solved! It was a bit of a hassel but I finally got Windows7 to boot from my X25. I had a bunch of SATA drives in RAID mode connected to my MB (Asus Striker Extreme) and needed to disconnected them first and disabled the RAIDsetup in the Bios. I upgraded the firmware on the X25 drive and voila! Windows7 accepted the X25 as installable target. After W7setup I reconnected the SATA drives and enabled RAIDmode only for the SATA drives. (Don't forget to check your HD boot priority in your Bios because it might change when reconnecting the SATA drives). Funny thing though, the Intel SSD toolkit still can't connect to my X25.