Tracking ajax requests with T5.4

Hi,

I'd like to track ajax requests (when do they start, when they are
finished) for some purposes:
1. Selenium UI tests - here I'd like to wait until ajax requests are
finished befor a test continues
2. Dynamic busy pane

I found some idea how it can work at
http://jumpstart.doublenegative.com.au/jumpstart/examples/ajax/loadingspinner
Unfortunately this won't work on T5.4. I had a deeper look to the code.
It seems that no explicit event is triggered when an ajax request is
started or ended. At least in dom.js a counter is increased/decreased
but this is not exported and it is decreased before the request is
processed - so not an ideal solution.

What would be the best way to hook into dom.ajaxRequest or alternatively
in ajax.js? Or should we change it in tapestry to expose this
information via dom events?

Kind regards,
Michael.