http://templates.dynamicweb-cms.com/TemplateTags/Dynamicweb-template-tags/General-tags/Translate%28%5BKey%5D,-%5BDefault%5D%29.aspx
it should be possible to use the translate tag on attributes.
I've used it (like below) on images and links, but they do not show up in the translation area on the template.
<img src="<!--@Translate(cartstep1, '/Files/Templates/Designs/SmykkerOgUre/images/dk/step1.gif', global)-->" alt="" />