Implementing Autocomplete on a dropdown

Implementing Autocomplete on a dropdown

I want to use the jQuery Autocomplete but the standard textbox won't work for me.  When a user selects something from the autocomplete, I need to be able to reference an ID so I can pass the ID to a details page so that it can query all the information correctly.

I figured using Autocomplete on a dropdown would work work better since I can set the ID in the value.  I just don't know how to accomplish this with the autocomplete since it only references one variable in the array.