Forms Data Controls :: Access The Instance Returned By Details Page?

I have this specific task: I have a contacts table, and when users view a specific contact in details page I want to display a button in the page (doesn't matter anywhere, but inside the detailsview control next to the "edit" hyperlink is better), when it's clicked I want to grab all the info of this contact instance and write it to Response so user can save it through the save file dialog. So far I have two problems1. How do I access the contact? it's displaying on the page but when I tried detailsview.dataitem it returns null, e.result in the datasource selected event handler also returns null...2. I can get the button (outside the detailsview control) to trigger the file download dialog, but how do I achieve the same thing if the button is placed inside the details view which is in turn inside a updatepanel?