I am confused by what you want. You want a text box on the main form, that
once a person starts typing, the subform will change to the closest match.
Then after the correct information is shown on the subform, you want to
press the up or down arrow on the keyboard and make the subform go to the
previous or next record on the list in the text box on the main form.
A look up box is not meant to completely fill out a form as you type, it
only fils in the current box. To do what you want, you will have to trap
each key stroke and update the subform each time. Although this can be
done, I wouldn't recommend doing it this way.
If your client doesn't liek using the mouse how do you expect to get from
typing in the search box to using the subform then back to the textbox to do
another search?
Kelvin