urgent: png hovers in ie5 mac not clickable with css only

I have two pages that have a ie5 mac specific problem that I want to solve with css only
So the page needs to be viewed with ie5 mac to see the difference

In the first page the anchors are not clickable due to the span that on a:hover displays the png background

http://home.versateladsl.be/vt665140/test-css/

Here I addded a js funtion so when a thumb gets clicked in IE5 mac
the url set in the href will be called and thus the thumb gets clicked

http://home.versateladsl.be/vt665140/test-css/clickable-links/

I want to alter the css of ie5-mac so the js wont be needed
The css in ie5 mac needs to be checked and gallery.css

Anyone??