We are also using 1.6 and I downloaded the same JCE.
The first time I tried this, it didn’t work and then I tried again and it worked, so there may have been a small typo or something. Unfortunately, I don’t have the one that didn’t work for comparison. Let me clean up anything sensitive in my server.xml and I’ll send you a copy. Maybe you can compare it to what you have directly and see what you find.