Directory plugin on subdomain site in multisite

hi there

I'm wanting to put the directory plugin on a site within my multisite - directory.mainsite.com

I've network activated but can't see it in the plugins on the directory site so am left wondering

1. if it's possible to do this
2. if so - how do I do it - clearly I'm missing something
3. if not - what other options do I have
4. if not - will the v2 beta be able to

cheers