Audio not appearing in Sony Vegas

[Beersy]

I use Sony Vegas 12 for my video editing. When I drag my videos into sony vegas, they dont have any audio or audio track. Only way I can fix it is if I export the video, thus compressing it into mp4. This would normally be fine, but then I have to re-render it in Sony Vegas, which messes up the quality.

TL;DR: How do I keep the audio wit the video without having to export it? (And yes, the video has audio when I play it in VLC, or in the Action! browser.

[radi]

What's your system audio sampling rate?