i think Paul is probably right... if going to a lead rather than leather didn't get it sparking the way it should, you have a problem with the frizzen. I had a similar trouble with my Renegade when i first bought it many years ago... give T/C a call and see what they can do for you- it may be possible for them to simply send you a new frizzen which will give you the quickest fix. Then, i'd stay with the lead flint wrap: be sure to set it, dry fire it three or four times, and then tighten the cock screw again. (your lock probably has a small hole drilled throught the cock screw at the factory- mine is just big enough to get a drift punch through, which makes it easy to snug things down, but don't get overenthusiastic.)
best of luck- you're gonna love your rockbanger when you get it going!