[Zope] set the MIME Type

I need to set the MIME Type of a DTML Method to "application/x-java- jnlp-file" but it doesn't work. According to www.zope.org/Members/anser/howto_dtml_mimetype I set the MIME Type in my DTML method (SimpleExample.jnlp) as follows: Content-type: application/x-java-jnlp-file , but the return of the server is: wrong mime type: text/html As anybody an idea? Thanks for any help!! Chris