If you are running the latest version of the WinIpac software, there should be an option to configure buttons as volume controls. I think it was one of the right-click options when assigning buttons. The catch is that your firmware needs to support it too. I think the latest Ipac version does, but only as of last year sometime. In my case I'm using the MiniPAC, and it does support it (although I bought it a year earlier so I had to send it away to have it upgraded, which Andy did for no charge!).