Firefox 4 : Is there a way to remove the red border in a required form input?

Question

When required is defined in a form field, Firefox 4 automatically shows a red border to this element, even BEFORE the user hits the submit button.

<input type="text" name="example" value="This is an example" required />

I think this is disturbing for the user as he/she asn't made mistakes at the beginning.

I wnat to hide that red border for the initial state, but show it when the user hits the send button if there is a missing field marked as required.

I looked at :required and :invalid from new pseudo selector, but the changes are for before AND after the validation. (from Firefox 4 Required input form RED border/outline)

Is there a way to disable the red border before the user submits the form, and show it if there is some missing fields ?