[Boikinov]

Try to manipulator the angle vector easily.
Didn't find anything in sourcemod SDK
Do I have to write my own matrix operator?

[pRED*]

Out of interest what are you trying to do with them?

The HL2SDK has matrix conversion function that aren't exposed because nobody has had a need for them yet. You could file a bug report, or just look at the code from mathlib and reimplement it in pawn.