So, what you're saying is you want to use xml to create info, then use vba to control the info, cross-platformatically? <layer id="John">John</layer>
Contain that in a an xml root structure and you can use the layer#John to get the info. If you use class="John" you can use layer.John to get the info. That's at least how you'd get css to set style to it. Guess I'd have to know a bit more about vba to know how to do it otherwise.