Perseo,
Refer to the following example on Ni developer zone on how to plot multiple 3D surface graphs:
http://zone.ni.com/devzone/explprog.nsf/6c163603265406328625682a006ed37d/a42072a6b4ad885b8625674e00072a4e?OpenDocument
Cyril
Cyril Bouton
Active LabVIEW Developper