I have never used a Brew Belt, but on my last two brews, an IPA and a Porter, I fermented at the low end of the spec for the particular yeast I used. After 10 days on both, my SG was only down to 1.020... a long way off from 012. So I moved my fermenters into a room that was 5-8 degrees warmer, and within 36 hours, I had a "new" krausen. So to answer your question, your brewbelt should wake those yeasties up just fine. Let it go for a while...like 2 or 3 days before you even consider repitching. Good luck!