saddle fit for a mule...help!!

[cheval <cheval@vci.net>]

Hi: I am posting this for a friend. Hopefully one of you has a
suggestion that might be able to help her out. She has a very nice 5
year old mule, about 15 hands, nicely proportioned (looks good under
english tack) but is having a problem finding a saddle to fit her. She
does a lot of trail riding, dressage lessons and may possibly move up to
endurance riding.
In her words: "I am totally unable to find anything to
ride my mule in.  Syd Hill medium tree saddles fit her topline, but I
can't
keep the cinch back of her elbow.  Ditto Wintec Aussie, Podium, med.
tree
Stonewall.  The Podium was rigged well back, but when I went to tighten
it
down, even with a crupper, was unable to keep it back.  Could you see
what
people there are using? as far as type of saddle, tree, rigging,
measurements, etc. She is a slight mule, no withers, straight back.  The

problem is her belly.  I'm desperate.
Thanks for any advice!