Use the ClassID property. Every Class has a different one. For a list of Class ID check out this topic: <a href="http://exchange.ni.com/servlet/ProcessRequest?RHIVEID=101&RPAGEID=137&HOID=506500000005000000A16A0100&HIsQuestionPoster=No&HTHREAD=000092833&UCATEGORY_0=_49_%24_6_&UCATEGORY_S=0">Where can i find the classID list for Labview 7.0</a>
Note: This list is for LV7.0, but it will most likely work for LV7.1. I will compile a new list sometime in the near future.