[development] textfield from autocomplete to show value not key

I have an autocomplete field picking-up text suggestion from an array($id => $name). When I start typing in the text-field the list of suggestions is properly showing the values (names) of the array. When I select a name however the key ($id) is shown in the textfield. The only way to show the name in the textfield is to populate the array as ($name => $name). But then $name is returned on submission while I need the key. Am I missing something? Thanx