Did you re-hydrate the S-04? Did you aerate or oxygenate? What was your mash temp? Three possible issues there for such a high gravity brew w/o simple sugars.
I agree that S-04 should be more than 40% of the way through fermentation by 10 days, it is usually fast and furious...you've got a problem. It is usually done in 3-5 days at most, and also has a tendency to drop like a rock, so it is difficult to get it going again once it decides to crap out.