sending base64 encoding

[Gus Delgado]

I'm sending an XML file back from the server to the client.
How can I send an encodingType of base64 on one of the Elements of the
XML file I send back?

example of what I'm trying to do:

<my-tag>
  <thisnormaltag>hello</thisnormaltag>
  <thisbase64tag encoding=base64>???</thisbase64tag>
</my-tag>

I'm really struggling with this? thanks
gus