The answer is, don't use Netscape or Explorer! If the pages are for a wap browser, why are you trying to view them on a regular browser?
If you are trying to create pages that will wok on both a wap device and a browser, you will have to detect which browser has requested the page and change the output accordingly (both the MIME type and the content)
Netscape/Explorer will download your page if the header type is set by:
header("Content-type: text/vnd.wap.wml")
As long as this header is in you dynamic WAP pages the WAP device should handle them correctly if your WML is also correct.
Paul