Yes - and 2 foot should not be a problem.
I would suggest finding a local dressage trainer to teach you and the horse about half halts (HH's). A properly executed HH cause's the horse to shift it's weight baclwards onto it's hindquarters - allowing the horse to lift it's shoulders - very useful for jumping.
A good jumping trainer can also design gymnastics for the horse to teach the horse how to shift it's weight backwards.
The point is even if the horse is built downhill it CAN learn to shift more weight backwards - but it will take a time for the horse to learn to rebalance itself AND develop the muscle to carry itself (what dressage riders call self carriage) and thus jump better.