From 100 to 66%, the named will constantly gain buffs that will remain the whole fight. A few buffs don't matter, but let them pile up and you'll have a lot more healing to do.
Burn Vhalsera down to 66% while using snaps on the reflection to keep aggro.
When he's below 66%, kill the reflection and be ready for the next one. You will keep getting that curse + reflection add until the end.
Vhalsera is stoneskined at that point. Lightnings will pop as in the heroic version. When the lightning fades on Vhalsera, some ice cage will pop around him and remove the stoneskin for a few seconds.
If you are positioned in the center of the room with the raid directly behind him, you don't have to move at all.
Below 30% the lightning stops, he gets rooted and frequently ports everyone to him. The encounter is reported as buggy and we have no clue how to get rid of his stoneskins at that point.
He also has an elemental aoe dot that needs to be cured fast.
Thx alot guys will try this out tonight and again sunday to see if we can moove 1 step closer to fullscale raiding 
Exactly, the IMP's that come at you initially are heroic and can either be off tanked or mezz'd and killed off one by one. Like Sude said the adds that pop after you kill one of the initial Imps, some of them are Epic spawns so if you just start killing the heroics you are going to get alot of adds that hit very hard.
Some of the smaller ones that spawn off kills of the larger ones are epic, some are heroic. The epic ones hit a lot harder. If you just plow through and AE the crap out of everything you can wind up with a bunch of epics beating on you. Like was mentioned above, if you mez the initial groups and kill them off one by one, you'll have a much easier time.
It's slower, but a much more sure way.
Have 2 chanters (if possible) choose sides (left and right), they focus on mezzing the hoard of imps, we have them stand in the hallway closest to the imps spawn point. I pull a single imp and drag it to the other end of the hall, kill it and the adds it spawns before getting another imp. sometimes a few get through, just focus on the small ones that spawn from the initial mob, if you kill all the big ones first with aoes the small ones will more than likely overpower you.
When you get to the other mirror mentioned (doppleganger mirror) have one member of your raid drop and click on the mirror, it will only spawn that one person. If they do not hit it the raid can pull it off and kill real quick. Reinvite and move on.
Imp room