Adding a custom symbol

Hi,

I need to generate 2 different versions of a document. I'd like to do
this:

    $ lout --'@Monochrome{Yes}' main.lout > bw.ps

and

    $ lout main.lout > color.ps

How can I add @Monochrome{No} as a default value somewhere?

Thanks!

-- 
Mark Summerfield, Qtrac Ltd, www.qtrac.eu
    C++, Python, Qt, PyQt - training and consultancy
        "Programming in Go" - ISBN 0321774639
            http://www.qtrac.eu/gobook.html