Thanks, Andreas,
Both #1 and #2 are by design. There was a configuration change between the Smooth Streaming 2.0 RTW and 3.0 Beta releases that required that we block them from installing side-by-side.
If you just want to test, especially with Live Smooth Streaming, then please just keep your existing IIS Media Services 3.0 Beta installation. If you want to go into production with IIS Smooth Streaming, please uninstall the IIS Media Services 3.0 Beta features (IIS Bit Rate Throttling, IIS Web Playlists, IIS Smooth Streaming, and IIS Live Smooth Streaming) via Control Panel / Programs and Features, and then install IIS Media Services 2.0 using either method 1 or 2.
Hope this helps. If this fundamentally blocks you in some way, please let us know.
-Chris