I had a already submitted a bug report for this:
https://openacs.org/bugtracker/openacs/com/acs-templating/bug?bug%5fnumber=1906
if this is a limitation of javascript then this bug should be removed... if there are no possible work arounds... if there work arounds then it would be good if this were fixed on the htmlarea end of things because this isn't just a problem with etp, it shows up in other places too.