I know I have done this before, but it isn\'t working today, nor can I find anywhere that explains how to do it. It could be my lack of sleep, but I suspect gremlins.
Does your xsd contain an attribute "targetNamespace" /schema/@targetNamespace that is similar to the namespace you are referencing in the xml?
"targetNamespace"
/schema/@targetNamespace
Examples:
XSD:
XML:
...
See also: XML/XSD intellisense not working in Visual Studio 2010