Thanks for the hack!
Just in case anyone wants to know (and sorry, if it's already been mentioned):
I also had the Text visible only in the default template. Inserting $unread in the other template (Kirsch) worked, but the URL to search.php contained backslashes. My first attempt to simply remove the backslashes from the phrases broke the default template. So I added a variable $unreadss in the product's xml-File ($unreadss = stripslashes($unread)

at around line 97 and can now insert $unreadss in the Kirsch-Template... works fine! :-)