If an input with type='image' is "clicked" with javascript the NAME.x and NAME.y parameters are missing from the request. That is beacuse HtmlInput.click(Event) is called and HtmlImageInput.wasPositionSpecified_ is never set to true.
The attached patch overrides HtmlImageInput.click(Event) which sets wasPositionSpecified_ to true and x/y to 0 (Same behaviour as real browser have). It also includes a test case.
Disregard the attached patch, it breaks HtmlInputImage.click(x,y). I attach a new patch when I fixed it.
New patch which also fixes the previous problem.
Thanks for the patch.