[QUOTE=Albrecht]I just to clear some things for me here, your help therefore, would be most welcome:
the Xp cap of the game is 8 mil total, so its 4 mil to each class... what are the implications of this?
when will I be able to obtain HLA's? how exactly does it work?
is it even possible to reach the cap? because I really would like to be able to cast lv 9 spells and so on...
so.... your ideas and thoughts... here... now

[/QUOTE]
You will obtain HLAs depending on what patch and such you have. A totally unpatched game will give you your HLAs when you're reaching about 3 mil xp for each class, which is 6 for a multi, and really really annoying as you won't be able to use it for anything.
The final (and only) official ToB patch (and maybe other as well) does so that you get your HLA at the same XP as a normal, non-multi/dual-classed character, thus lowering it to ~1.5 mil for each class, 3 mil total.
And yes, it's very possible to reach the limit. I always do when playing 2 characters, and 3 should be possible as well. I'm not sure with larger parties, but I don't do Watchers Keep very often either. So you might be able to get some XP there.
And you will get Time Stop, sure, but not untill a total of 6 mil xp, which might take a while, and in bigger parties you even might not get it. :/