Replace non-wicket attributed sections of a html document

Hi,
I'm currently writing a CMS in wicket. One of the things I'm wanting to do is make it nice and flexible to be able to design new templates for rendering the page.

I'm looking at producing an image gallery at the moment.

For the moment I'm using <DUMMYimg wicket:id="image1" src="dummy.jpg"> or something similar in the html files, which is fine.

image1 would then be replaced by a Static Image of something like "/images/gallery/realImage1.jpg" or whatever..

The problem is, I'm wanting to be able to make it as flexible as possible for the designers to be able to use what they want re javascript and markup to get the page how they want it.

So for example, instead of referencing "/images/gallery/realImage1.jpg" via the wicket:id of an img tag, the value may want to be put into other parts of the html markup:
e.g.
<DUMMya href="#" onclick="showPreview('/images/gallery/realImage1.jpg','1');return false">
or
<DUMMYimg onmouseover="renderImage('/images/gallery/realImage1.jpg')>

or anything else really!

So is there anyway this could be done?
Maybe there is a way to process the HTML and replace data, so for exmaple I could have something like:

<DUMMYimg  src="$image1$">
<DUMMYa href="#" onclick="showPreview('$image1$','1');return false">
<DUMMYimg onmouseover="renderImage('$image1$')>

and replace $image1$ with '/images/gallery/realImage1.jpg' while rendering the page.

Anyone any suggestions?
Thanks
Andrew

note: remove the ref to DUMMY when reading this, I couldn't get nabble to display properly with the tags in.