[Help] Customize Elements enchantment and Other Question!

Hi guys, I have a couple questions!.

1. I want to put a limit for the enchant of elemental stones in the weapons, they're level 7 and I want to put them till level 4, how should I have to do it?

2. I want to make able the posibility to enchant with this elemental stones Pvp items and Infinity weapons.

3. If a skill can not be enchanted with giants codex and masterys (just because they're not working correctly), how to fix it?.

Im using L2jserver!!!!

Pd. I'm sorry if I asked something wich is already posted in the forum, but I'm really bad searching stuff  :-[

Thanks in advance!!!  ;D

Peace,

Quintesencia.