How to use custom data?

Is it possible to use custom data with this module? I took a quick look but I didn't see an obvious way. See the demo here:

http://jqueryui.com/demos/autocomplete/#custom-data

What I want to create is a text field into which people can type the name of a store. My PHP AJAX callback will return an array like the 'projects' array at the link. Only the label will be put into the text field, and when the user selects an item from the list I'll use the other data associated with that label (in the example, 'desc' and 'icon') to fill out other text fields. I'm aware of other ways to do that, but doing it in the way shown in that example would be best.

I've already spent some time moving http://drupal.org/project/autocomplete_element to D7 for my own use (not as part of that project), but if this module can use custom data that might be better.

Also, unlike autocomplete_element, it doesn't look like this module can send extra data to the backend; it appears to only send the search string the user entered. I'm aware of ways around that too, but it'd be nice to find an all-in-one solution.