Bind input content of auto-complete input field

What I am trying to do:

I got an input field with auto-complete enabled.
If there are no results from the auto-complete, I want to use the input (typed) value in the input field to bind it to a server connect action (or hidden form). But the value from the data bindings menu of that (auto-complete) input field is not equal to the typed input text, because the value is set by the autocomplete function. So how can I grab this typed text??

Thanks for any help in advance.