Cannot start the "Exploiting an Opening" quest chain.

Hello,

I have a bit of a problem trying to start the Arthas heart quest line. I did my research and did the shadow vault and the crusaders pinaclle quest chains (from Tirion Fordring), which should have given me the option to get the "The Skybreaker" quest from Marshal Ivalius, but it didnt.

And if I get to the skybreaker and find Thassarian, he wont give me the quest "Exploiting an Opening" which start the Matthias Lehner quest line.

I've found the entire quest chain in the wowhead comment section (http://www.wowhead.com/quest=13386/e...ing-an-opening) which illustrates the path I need to take in order to get the wanted quest chains.

As I mentioned, i've already did the shadow vault and crusader pinnacle quests.
Tryed to open up a ticket, but the GM suggested to look through the bugtracker, which I did before (maybe I missed something)

Any input would be really appreciated.

Thank you for your time.

It comes much later on, after The Fleshwerks, there is an escort quest there which unlocks your quest