InfoPath Dev

I have a form that loads data from a secondary data source (via a web service) into a drop-down list box when the form is loaded. I have added a "changed" event handler to the drop-down list box that executes a WebServiceConnection on the main data source. The results of this are loaded into a repeating table.

All of this works fine in the InfoPath client, but in the browser changing the selected value in the drop-down list box doesn't cause a postback. I tried changing the Postback settings for the drop-down list box from "Only when necessary for correct rendering of the form(recommended)" to "Always" and it still doesn't work. Then, when I give up and click on the "Close" button, the form in the browser does a postback before exiting and pulls in the new data just as it displays the "are you sure you want to exit" dialog.

Why doesn't the postback work in the browser?

In further experimentation, I found that if I upload the new version of the form template (with the "Always" postback option) via Central Administration, then it works. If I use the target web site and deactivate the feature, upload the new version, then reactivate the feature, it doesn't pick up the changes.