This is usually done by having the armor be different entities from the character, then the armor can be swapped in/out dynamically. The character has "bind points," usually bones, sometimes specific triangles, where the armor can be attached. Then the armor follows wherever the character goes, inheriting its transforms…
ahh, now i see, interesting stuff. looking at unreal engine 3 i see it has an option like what you outlined- Ability to add game-specific notifications at specific points in the animation. Tool for graphically placing Sockets on bones to be used for attaching objects to the skeleton in the game, complete with preview.…