I would say use splints or polo wraps. Sometimes depends on the horse on which to use. My 4yr hates splints but it fine with wraps. But I suggest you use them all the time when you jump him unless your jumping xrails...
Also he may have used to refuse jumps because since you were new, maybe you were reluctant and he could feel it. It may have also been because he was new or maybe young? Im not sure about your situation (:
Again, my 4yr does that sometimes, he just needs his self esteem built up. Make sure when you do jump not to pull on his face over the jumps... and just keep at it and don't jump him every time you ride
Ok...im done talking now :P