Hi,
first, you need to get invisible as eskilajnen in his thread "[Exploit] Invisible as shadow priest!" explained.
http://www.mmowned.com/forums/wow-ex...ow-priest.html
the only difference is, that you recast shadowform on you when you are still on your mount.
by doing that, you become visible again, but your Inner Fire-Stacks won't fade when struck by a melee or ranged attack from players and mobs!
http://www.bilder-hochladen.net/files/6d0t-i-jpg.html
This also works if you got a shadow and a disc specc.
Just buff Inner Fire with this bug in shadow specc. Then change your specc and you got a 30min Inner Fire buff which doesn't loose stacks against Players and mobs.
mfg
PS: Sorry for bad English