You may want to check the following example, as it shows how to simulate keystrokes. It includes a VI called "Simulate Keyboard":
http://zone.ni.com/devzone/devzoneweb.nsf/opendoc?openagent&3B1B0B401B12F80D8625683C006F1253&cat=71359FBAD517F4CB862567E0007B6F6E
Best regards;
Vargas
www.vartortech.com