XMLHttpRequest not populating Query variable (yui connection manager)

I have been working on a clearsilver backend replacement for this yui
connection manager example:

http://developer.yahoo.com/yui/examples/connection/post.html

but Query.username and Query.userid are not being populated.  When I
use a html form and post to the same clearsilver script these
variables are populated properly so it is something with the way the
connection manager is doing its business.  Any tips or suggestions?

culley