UpdatePanels and Wizards

At the heart of my new website is a little control that does a dynamic lookup of a name as you type in a text box. Internally, I call it a PartyLookup (as the core table it searches is the Party table). Today, I am trying to add one of these controls to a rather nasty page: it has a wizard inside an update panel all in a modal popup extender. This all worked when the popup window did not have a wizard, but the page is complex enough that I decided I needed to break it up into 2 steps, hence the wizard. But my lookup control stopped working, as the dynamic javascript I generate to handle the AJAX calls was not getting emitted via the partial postback when I changed wizard steps (the lookup control is on the second page).

I searched Google for an hour, trying everything I could find. Finally, the following 2 changes worked:

For javascript I generate in the server-side code, I needed to use
ClientScript.RegisterClientScriptBlock, rather than Page.ClientScript.RegisterClientScriptBlock. This is a mysterious fix, but it works.

Second, for script that I want to include from an external source, I needed to add:
if (typeof (Sys) !== 'undefined') Sys.Application.notifyScriptLoaded();

Together, these two calls seem to have gotten my control working in this new environment. We will see...