Re: regexp for scheme blocks in lilypond language

Another small problem I cannot understand.
The block can have also an optional ' before the brackets, like in this 
example:

#'((basic-distance . 12)
    (minimum-distance . 6)
    (padding . 1)
    (stretchability . 12)))

% checker


I've added '? to the regexp I pasted before:

environment scheme_block delim `#'?\((\(*)` @{1} + ")" multiline nested 
begin
   environment scheme_block delim "(" ")" multiline nested begin
     include "url.lang"
   end
end

The first delimiter works fine, but the highlight goes over the end 
delimiter and the "% checker" string is highlighted as well, while it 
shouldn't.

I guess I'm doing something stupid, but I can't see it.
Thanks for your help, it's almost done :)