custom room properties and hashtable

I want to use custom room properties in my project using UnityScript. I can't seem to get anything to work. Even with:
import ExitGames.Client.Photon;
in my script, the simple declaration:
private var roomProps = new Hashtable();
fails with the message:
BCE0023: No appropriate version of 'ExitGames.Client.Photon.Hashtable' for the argument list '()' was found.

I read in another post that I may need an older version without Windows 8 support (I use Win7) but where do I get it?

Can I get a even a trivial example of setting and retrieving custom room properties in UnityScript?

thanks,
Don