I use Vegas Pro 18. I create (among other things) test signals for my home theater. I have trouble creating a USB file with video and 5.1 sound that is recognized by several players that work perfectly on other sources, but do not recognize the sound created by Vegas Pro.
Are you using Vegas to render to 5.1? If so, which format and template? Or are you using Vokouder?
I am using Vegas to render to 5.1. I have used several templates, but none of those have worked. Can you suggest a template that will work? Do later versions of Vegas support 7.1?
Vegas no longer provides a licensed Dolby encoder, so I am guessing that might be part of the issue. Your players could be looking for a Dolby file. If you have an older version of Vegas and DVD architect, you could render your wav out as a multitrack and finish the audio in the earlier Vegas version. I can't remember when they removed the Dolby license.