Hi,
I've just committed some light docs on geometry transformations
and parameter substitutions.
I'll eventually blog about both, for the time being, anyone interested
in it could review and provide feedback:
http://gridlock.openplans.org/geoserver/2.0.x/doc/en/user/styling/sld-extensions/index.html
Cheers
Andrea
--
Andrea Aime
OpenGeo - http://opengeo.org
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