[HELP] Refresh Skill Cooldown

[NightCr0w]

L2J Revision Number: 4497
L2JDP Revision Number: 7780

I have a private l2j (Freya) server, and i like changing things on my server (to make it a unique server).
So this was 1 of my many ideas, but unfortunately i dont know how to do this:

When ghost walking, exciting adventure or wind riding are being used (effect applying),
i want (ONLY for the duration of these buffs) Shadow Step to have a much lower reuse time (without affecting other skills' reuse time. so, only that 1 (Shadow Step) skill's cooltime reduced, while 1 of these buffs effects are active.
( for example, shadow step will have a reuse-delay of 4 seconds just for 30 sec. Then, when the buff ends, the cooltime of this skill must turn to normal again. Is this possible? can anyone help?

Or maybe another way: To cast shadow step automatically during these buffs, right BEFORE a physical skill is used.
(so skill is used, but before the effect/dmg player is ported behind)

Thx in advance.