Coordinates in mapped system, expressions (X.Y.Z)

Hi there
Im student, and working now on SAW Pressure sensor
My PC have 4Gb RAM and I cant use 3D for this modeling. only 2D

So, my surface material is ST cut Quartz, Euler Angles is (0;132.75;0), X-propagation os SAWs
picture of crystal plate position here
img545.imageshack.us/img545/2407/img9314u.jpg

And because in 2D we see only X and Y coordinates I need to use mapped coordinate system to rotate system of material in true propagation for my screen. Plate of quartz needs to be normal to Y, and saw propagation go by X

I have cheked all forum about expressions for coordinates in mapped systems, but found nothing!

PLEASE ANYBODY, MAY YOU EXPLAIN ME THIS ITEM?

My diplom will be on this fryday, and teacher found a mistake in this
thanks