OSB Xquery variables do not show in binding list

check here why:

http://rogervdkimmenade.blogspot.com/2009/07/xquery-use-within-osb-watch-out.html

if you don't actually use the variable in your XQuery, even if it's in the method signature it's not appearing in the binding list.... does this make sense? Perhaps yes, but it's not that intuitive.... at least they should display a warning....