Autocompleter - get rid of default selection?

Running Scriptaculous 1.8.1 I'm experiencing an issue with the

As part of a search page, I've added and autocomplete field. During
entering text, the first entry in the autocomplete list is
automatically selected- once the user hits enter (regardless if that
is the entry he's looking for or not), the form is submitted.

I'm looking for a way to not have any autocompletion entry selected by
default- instead I want the user be able to do that by using "cursor
down" initially to actually step into the dropdown list.

Thought that the "autoselect" property of the Autocompleter did
control that but apparently doesn't.

Any ideas?