Hi, i was lucking for this and finaly found how to do it, so here what i've found.
To make a specfic class quest you'll need to set the value
"ZoneOrSort"
to this ID :
- -81 for a Warrior quest,
- -141 : Paladin
- -261 : Hunt
- -162 : Rogue
- : Deathknight
- -262 : Priest
- -82 : Shaman
- -161 : Mage
- -61 : Warlock
- -263 : Druids
Source : http://www.trinitycore.info/w/Quest_templat#ZoneOrSort