[rules-users] DSL regex support

I just upgraded to 4.0.3 and want to take advantage of regex support for my DSL. Specifically, I want to be able to use a character class at the start of my expander expression to allow the first character to be case insensitive. For example (in the expander definition): [when][Ff]act value is "{value}"= SomeFact( value == "{value}") So that the rule could be written as "Fact value is..." or "fact value is....". But I think this conflicts with a syntax that the parser uses to add constraints to the previous declaration (according to the reference docs, section 6.7.4). If I try to use the same character class construct anywhere other than the first character it works fine. Is there some escape sequence I can use to get what I'm looking for? Simply escaping the [ and ] with \ didn't work. Thanks, Adam Lewandowski