It isn't. If you need your data to have namespaces, or a different structure
than the one Form Builder creates, you'll most likely want to transform it,
say with XSLT, when your end point receives it from a `send()`.
A while ago, we had implemented support in Form Builder for mapping controls
to nodes in your own XML document. (I'm not sure if that implementation also
supported namespaces.) But we found that it added a lot of complexity
throughout Form Builder, and created an additional concern for every new
feature, so we decided, at least for now, to stay with a simple
automatically generated data format. I hope this won't be too much of a
problem in your case.