How do I populate an XSD instance programmatically?

[bsdbsd]

I need to create valid XML data. This data will need to be able to be
validated against an XSD schema. The tool I am trying to use is Xerces
C++. Being new to both C++ and XML, I am a little stumped at how to begin.

http://xml.apache.org/xerces-c/

I was given XSD schemas that my raw data needs to be converted to. My
initial approach has been to create an "empty" instance of the DOM
structure defined by the XSD file, and then "plug-in" my data in to the
proper nodes. This is apparently not the right way to do this, as I can
not find any examples of this on the net.

If I understand what I've been reading correctly, I need to create a
root node, then manually add all the nodes required to place my raw data
in the proper locations of the hierarchy. It would seem there should be
an easier way to do this, since the DOM structure is already defined in
the XSD file.

Also, is it true that the DOM object cannot be verified in RAM, but must
be saved then reloaded as part of a "conformance" test? Again, it would
seem there should be an easier way to do this.

Most of the examples I have found on the net use XML schema instance
examples that have been contrived by hand. Or they load an existing
instance, tweak it in memory, and then save it. There are many examples
that show how to programmatically create simple XML data that does not
need to conform to an XSD. Are there examples of how to populate an
empty XSD instance?

I feel like I am missing something basic here.

Thanks!