Thanks for the help, that works well.
Now I am trying to do a reset of the pitch, yaw, AND roll with a custom value for the pitch and "zeroing" for the yaw and roll. I would like to have the yaw and roll reset first and then set the pitch. I really can't grasp the correct order for these transformations; this article is the best I could find:
http://docs.worldviz.com/vizard/Link_operators.htm
If I try to reset the yaw and roll first with a preEuler using the opposite values from the tracker, I get weird issues where I am moving or rotating the wrong directions. Any help on the best order/functions to implement this? I'm using the IS-900 for both position and euler.