TwonkyMedia really needed to release their TwonkyMedia Server to all Windows Home Server. Currently, the addin is only available to HP and Fujitsu-Siemens SCALEO owners. TwonkyMedia announced in their forums:

We have a special version of TwonkyMedia that runs as an Add-in on WHS. Currently it’s only available when you buy an HP MediaSmart server, but we’re hoping to offer this to all WHS users — as soon as it’s properly tested…. We understand that many of your have built your own Windows Home Servers and plan to sell a version designed for you guys as well. I don’t have an ETA yet, and won’t have one for at least a week because I’m at CES all this week.