Here's an example comparing forms with and without a hyphen in their name:
http://jsfiddle.net/davemerrill/nEPLL/2/
Far as I can tell, the visual highlighting works either way, but I don't know how to access the form in code with a hyphen in the name. It may not actually be possible, because the form name isn't a valid js variable name. There may be some bracket notation way to access it, but I don't know what it'd be.
What makes you need the hyphen there? The name of a form isn't seen by the server, it isn't even required except for angular validation. Can't think of a functional requirement that would make the hyphen mandatory.
Dave Merrill