__doPostBack not working for updatepanel on page where enableviewstate=false

[cobra560]

I have an update panel on a page, and am using \[code\]__doPostBack\[/code\] on a control inside the updatepanel called from javascript to do a postback and update the panel.Everything works fine, until I set \[code\]enableviewstate=false\[/code\] on the page.The javascript still fires, but nothing happens on the server side.