Problems with extended (old) raid, and still getting fresh instance

[Noctus78]

So, for years i have saved raids on an alt like:
ICC @ LK
DS @ Ultraxion
MSV @ Elegon
SoO @ Garrosh*

Each week i would extend the raid id's on my alt. make a group in the groupfinder tool. log off with the alt, log on with the main and join the raid my alt created.
My main would be able to change the raid difficulty / size after he got leader to match with the saved ID.

Since this week only ICC works for me.
DS and MSV i only get into a fresh instance since this week.
(SoO i always had trouble with)

Anybody else have this problem. Or how do you work around this for mount farming?

[TOM_RUS]

Make sure character with lockout still leader before entering raid with other character. And apparently it's not doable with MSV, ToT, Firelands anymore. You can thank Blizzard for those changes.

[Onikaroshi]

They broke a lot of lockouts, including the fact that a character with a lockout will still get the boss kills even if they're not logged on.