The way you model pulleys in any CAD program is by wrapping the profile of a belt around the pitch circle (The pitch circle is a circle of diameter (Number of teeth * Pitch of pulley / pi)). Typically you start with a drawing; I’ve attached the drawing for an HTD 5mm belt below:
Note that you don’t need the 3.05mm dimension shown above. The pitch line is halfway between the root the teeth and the outer edge of the belt, so (2.06+3.80)/2=2.93 mm up from the tip of the teeth. You can then use tangent dimensions and angular pitch sizes to locate all the features of the belt, using only the methods above. It should be pretty straightforward (or so I say, having done this many times), but if you have any trouble understanding, feel free to ask further.
I won’t go into excessive detail in just this reply, but if people are interested I will write up a full-length tutorial on this. I can also write one for gear and sprocket design as well if there’s any interest.