Oh, correction – I see PowerShellPack.msi. Sorry, I saw that and thought of PowerGUI for some reason, since it uses PowerPacks.
Anyway, yes, PowerShellPack.msi is the installer that brings some of the up-level command modules to down-level versions of Windows. But I might still tackle this with WMI. I’m not sure the PowerShellPack works on Win2008 (which is Vista-quivalent), for example.