What I did is writing another simple layer over UNA which makes the changes to the code in the buffer before it is sent to the browser. This way I was able to make any systematic changes in the resulting page.
I can publish all code here but:

• I am not a programming  professional, so this is not a professional level program
• it is specific to my site, not generic.
• I can not provide any further support for it

But if you want to see the code just to inspire for a solution, I will publish.