Jan will it help to press the seams to where they want to go rather than to the dark side...if that's what you are doing. How about lightly sprinting the seam with water,then press. Let the steam and heat do the work. Then while it's still warm slip the block under something heavy like a book, a pressing block if you have one. After it has cooled down see if that has helped. I've been using this technique with my little 1 1/2" 9P's.
Watching Cyclone BB.