I've never made an image map with rollover images superimposed on it as links.
Could you put the main image as a background image then put the rollover link images in the div? You could position the rollover images in the correct places on the background using position: absolute.
Javascript is usually used to create rollover image links but there are some css examples. Google javascript rollover image links.
Code downloaded to my PC will be deleted in due course.
WIN7; IE9, Firefox, Opera, Chrome and Safari for Windows; screen resolution usually 1366*768.
Also IE6 on W98 with 800*600 and IE8 on Vista 1440*900.