It's an interesting way, but a bit tedious, don't You think?
Here's what works with 99% less setup time:
*Go rght outside the starting town
*find a spot without NPC soldiers
*gather some monsters and let them whack You once
*casually walk to the next non-fighter-npc or a sign and click on it.
*Leave Your gaming machine on for the night
This takes advantage of Sacred not letting You get hit when a message window is up. The monsters are still around, though, and are never tired of trying to kill You. Your SB increases normally
Tried and tested.
~Sylv