Be aware that on end user systems APOs must pass through the Windows Logo program as part of audio driver package in order to be signed properly to load in the audio system. Otherwise the APOs will not be used. Frank Yerrace Microsoft This posting is provided "AS IS" with no warranties, and confers no rights. From: wdmaudiodev-bounce@xxxxxxxxxxxxx [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Dennis Scott Sent: Sunday, October 11, 2009 11:23 PM To: wdmaudiodev@xxxxxxxxxxxxx Subject: [wdmaudiodev] Using APO LFX with virtual audio driver in Vista/win7 Can i build an APO LFX in vista/win7 for my virtual audio driver?? 1. I modified swap sample and tried to associate with my driver but i am not successful. how exactly can i associate the APO dll with my driver? 2. Any special support has to be provided in my driver to associate an APO with it? dennis scott