Angle and y axis rotation in Max

Well,

I feel stupid today. I've made a patch where you can place a sound anywhere on an x y axis and then walk around it. When you walk around it there's 360 of panning and the distance between the two changes the volume. It's like a small virtual world of sound :)

The problem :) Which I've been trying to solve all day is. I can't change the point of view. You could call it the field of vision. The "character" always looks straight forward along the y axis. I want to be able to ROTATE so you can look for sounds.

I get the angle between the "character" and the sounds with cartopol.

Rotation is the main question. Found this slider but i don't know how to implement it in Max http://www.essentialmath.com/GDC2012/GDC2012_JMV_Rotations.pdf .

Understand me? :/