SIG Alternate

[Anders Host-Madsen]

I'm trying to write a paper with the SIG Alternate class. It seems
LyX has a layout for this class. The problem I have run into so
far is the following. The SIG Alternate layout file does not
have any theorem-like styles. This can be solved by adding the
Theorem module. But then I run into the problem that
the 'proof' environment is already defined in the
SIG Alternate class (the error message is 'Command
proof already defined'). How can I resolve this conflict?