Good news guys, I have the solution for the "mach_kernel" problem.
Well, at my first try, everything worked well with the same steps as neilhart. Then, I erased my RAID-0 and tried it like 4-5 times and always got "mach_kernel".
PLEASE use the exact same steps like neilhart !!!
After you have done this, open Terminal and type (I have the same disk numbers like neilhart!)
diskutil mount disk0s3
You'll get this: Volume Boot OS X on disk0s3 mounted
Then open "Boot OS X" in Finder and search for this file and open it:
com.apple.boot.S/Library/Preferences/SystemConfiguration/com.apple.Boot.plist
This file will look like this:
Check here if you have the exakt same RAID Identifier like you've copied from the Disk Utility to your
org.chameleon.Boot.plist
In my case, there was another UUID in there and I replaced it with my RAID-UUID. Of course, you have to make it with the second "Boot OS X" partition of your second HDD or SSD (diskutil mount disk1s3). After that, unmount both Boot OS X partitions (in terminal or in Finder).
diskutil unmount disk0s3
diskutil unmount disk1s3
Restart and be sure, that your RAID HDDs or SSDs are on first boot priority in BIOS.
This worked for me and after two days of trying, I can use my SSD-RAID-0 again
Thank you again neilhart, great tutorial here!