I have a zope site where users can access content using either html browsers or wap/wml devices. I want to customize the standard_error_message dtml document to display errors in the appropriate format for each user. For example, if a user tries to access a non-existent url from a wml browser, they should get a nice wml page back saying that the page was not found. Heres the problem. Although I have customized standard_error_message to display a page in the right format, the code in ZPublisher/HTTPResponse.py (exception method of HTTPResponse class) checks the error page I generate and, if it doesn't see "<html>" or "<!doctype html" at the start of the page, it wraps my page in some html by calling _error_html. Thus I get a small wml page wrapped in html :-( It makes no difference what the content-type header is set to - I'm setting that correctly for the users browser. Is there any way I can alter this behaviour short of changing the code in ZPublisher/HTTPResponse.py? Thanks in advance Noel Duffy.