Hello v007 Welcome to the Seven Forums!
In order to salvage the 7 installation you will have to do a little work while booting live from the 7 installation dvd. The first place to learn to build a new boot sector and BCD store is in the guide seen at Bootrec.exe Tool - How to Use in Windows Recovery Environment
Apparently all the boot files which includes the bootmgr file or boot loader as well as mbr information is on the drive where you have the Vista installation. The Startup repair wouldn't work for this since the lack of anything on the Raid 0 disk is too extensive.
The alternative option which is often not necessary to insure the 7 install is made bootable would be an Upgrade to Repair type of repair install which still preserves all programs, files, and folders while may need to see some device drivers
reinstalled fresh in seen in another guide at Repair Install
With a little typing in at the command prompt option of the Repair tools on the 7 dvd you can save a good 80min. or so however. You will want to unplug the Vista drive first however which will make the 7 drive the default boot device. Once you replug the Vista drive back in a trip into the bios setup to change the boot order back to the 7 drive seeing that set as the first drive on the top of the list of drives would be needed.