[XML-SIG] how to embed a DTD which is external

[Johann Cohen-Tanugi]

Hi there,
I am using DOM to read an external DTD and then create and fill a
corresponding document. Then I save the result with PrettyPrint.My
problem is that the resulting XML file has the name of the external DTD
which is fine, but I would rather have the DTD copied in extenso, id est
transforming the external DTD into an internal one.

I did not find the way to do that easily. Can someone help me?

Johann