[Zope] popup-windowLink with structuredText

Dear List, does anybody know how to perform a link with a popup window within structuredText? "myLinkText":javascript:openwindow() does not work because the brackets "()" are not rendered by the stx of zope. Is it possible to render also the "()" or does anybody know to implicit call a function via variable i.e. without the brackets. Thanks for your help, Elena