Copying only *.files from tree

[Gilson Soares]

I'd like to replicate a directory structure but only copying *.<anything> 
files.

rsync -a --include="*.rrd" --exclude="*" /var/www/html 
taurus::pegasusdata/var-www-html

Didn't work.

One additional issue is *.rrd files only exists 2 levels bellow 
/var/www/html/, not in /var/www/html itself.

Do I missed something ?

-Gilson Soares