One may use ATMEL Generic DLL file as mentioned in the ATMEL Application note "USB PC Drivers Based on Generic HID Class",
http://atmel.com/dyn/resources/prod_documents/doc7645.pdf
Use LabView DLL Library Import function to link to this ATUSBHID.DLL File and use its findhiddevice, readdevice, writedevice, start and stop functions to communicate with ATMEL chips. I could successfully communicate with AT90USB1287 with this.
Same DLL can be wrapped in C#, C++, VB etc. to communicate with ATMEL Devices.
Your ATMEL device should first be detetected by the system and comes under the Device Managers list under generic HID class or otherwise. Windows based drivers normally comes with AVR Studio 4.
