Left canter lead HELP.....

Yes, I saw the riding tips thread and no I didn't read through all of it. With that said I need help before I go CRAZY!!!! My Regan is so right sided that she even walks bent to the right if given the chance. So, I have been working a lot to the left and working on bending (to the left) and we are getting much better but the left canter lead is a no go! I even have someone else riding/exercising her and she is having the same problem. Regan is only 6 and is still quite green. I have worked on her back end to get that working in the hopes that that would help. I do ask for the canter at a corner, on circles, in an arena, in a field just about anywhere and she will not pick up the left one. She will counter canter all day long on a 20 meter circle! I did get her to pick up the left lead this week but couldn't get her to stay on it. That may be my fault as when we finally did get the lead I was pooped!! Now mind you, my darling horse has discovered jumping (over a 4 1/2 to 5 foot fence uphill). When she does come over it she has the most beautiful left lead. WHY WON'T SHE PICK IT UP FOR ME??????? What am I doing wrong???? It is driving me crazy. I have talked with trainer, riders and anyone who would listen and I think I am doing everything right but still no left lead. Anyway, any suggestions would be great!!! Oh, how I ask for it is to sit up and quiet, outside leg back , nose "tipped" SLIGHTLY to the outside, inside leg at the girth. And as far as I know there are no previous injuries to the left leg or anyother part of the left side (she has been in the family since she was 3). Am I doing something wrong? Thanks guys!