need help - step by step multi network

Am totally confused.... maybe I am missing the point completely as I have tried all the steps in install and also this http://coreyjmahler.com/topics/setting-up-a-wordpress-multisite-install-to-use-multiple-domains/

we have domain... smeak.com, *.smeak is enabled ... so far we have multiple sub domains e.g. music.smeak.com... all working perfectly...

Our root blog (smeak.com) is a BuddyPress install also been running well for months.

WHAT WE NEED
============

We are trying to set up a test site called musicmatrix.co.za. I have done all the wildcard and DNS stuff and if you type in that URL it resolves to http://smeak.com - loading the main blog.

We need musicmatrix.co.za to share the WP install, as in themes and plugins, and MOST importantly users... BUT it must be a seprate BP site with its own forums, blogs and groups...

So we have tried

- Domain Mapping
- Multi-Domains
- WP Multi Network
- Network+
- BP Multi Network
- WordPress MU Domain Mapping

whatever we do... musicmatrix.co.za just keeps on reverting to http://smeak.com the main blog on the initial network...

I am totally lost, believe me tried everything (SUNRISE on, wa wa wa) ... next week i need to demo the musicmatrix BP site - and I am lost