IVR application on Nortel MPS 500 not working with ASP.NET MVC

We have a web server running IIS 6.0 and ASP.NET MVC, that is serving plain xml. The IVR Browser is not accepting the xml being output by the web server.

The Controller just returns a normal ActionResult, but changes the Content-Type to text/xml.

The View is just a typical aspx page, but instead of html, we've put xml in there instead. When we view this in a browser, it properly returns the xml in the View. In the I开发者_如何学CVR, it just bombs out. If we remove the Page Directive on the View, then the IVR works.

Does anyone have any idea what the Page Directive changes in the output of the view?

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Problem Solved:

The problem was not with the page-directives at all. The Nortel MPS 500 browser was not ignoring whitespace at the top of the xml document. So to fix the problem, we had to change our Master page, and put the <?xml version="1.0"> on the same line as the master page directive.