replace item in armor slot

I created armor that has changes to it and it has to heal its self base on factors witch works so good so fare but I notist I cannot replace the item in the slot I can detect the armor slots but cannot replace or place armor in them unless I use minecraft /replace item command but I found you cant use commands if cheats are off and this would not be any good on servers also it puts a message in chat allot of negative with commands on this. so wonted to know if there is a way for me to set item in player slot 2 with out /commands? I been working on this mod and I never been closer to completing it and I just need to 1000 more mod elements before I can release my update.