Modifying XML tag attributes/properties in .net

[francislang]

I've got an XML document that returns various bits of information from my webservice. The tags and some values are created inside a stored procedure. I then load the XML into a domXML object in .net because I want to insert a PDF file into the <PDFFILE> tags that were created in the SP.

Question: I need to change the property/attribute of the <PDFFILE> tag to tell the client(webservice) that it is base 64 encoded. e.g. <PDFFILE xmlns:dt=""urn:schemas-microsoft-com:datatypes"" dt:dt=""bin.base64"">

How do I go about changing this in .net?

Any help would be most appreciated.