LOL, wait wut??
For as far as i'm aware they should support up to almost anyhting. I think it is a strange answer to just say we don't support it but that's just my 2 cents. And RSAT is an addon for Windows, not a Windows Component per say.
And as said, we have it running in our W7 VDI desktops.
How are you trying to install the RSAT tools btw? We don't install it using the Software and Packages tool in Windows itself but the stand alone installer.
Could you try and download the stand alone installer and install with this? Make sure to enable the Windows Update service before you begin and make sure to disable it after you end installation, otherwise this appstack will enable Windows Update service and you really don't want that.
Download Remote Server Administration Tools voor Windows 8 from Official Microsoft Download Center