Did you ever try to run VC2 SP directly on your server?

Negative ghost rider. Does VC2 work without a sapi installed on the server? Or should I try installing that "other" speech engine on WHS 2011?

You can't use the regular engine (sapi) on server, but you might be able to use the SP version.

http://voxcommando.com/mediawiki/index.php?title=Version_2

There a quite a few differences which are explained if you follow the link.