Make sure you use 'backup activation' in SAM to ensure you avoid getting relocked in the future (this is according to Musclenerd)
http://twitter.com/#!/sbingner/status/57622810171932673
Install SAM by doing this:
Add http://repo.bingner.com as a repo in Cydia
Install SAM and SAMPrefs
Under settings there should be the 'backup activation' option
Hope it all works out for you bud!
Do you install SAM before or after updating to 4.3.1 (if on 4.2.1)?