Just tried the new beta 10 version, nice work on the dynamic sounds man!

The custom achievement background shows up in-game (where it matters), all though not in the preview display under options, that may be a small bug I'll have to fix.

I noticed the read me has some extra directions which may be sparr's problem. Under audio options, in the Voice Packs section, you just have to press Load, then choose the voicepack.