nsIDOMDocument in Java

Hello,
I need to manipulate a dom tree from a java class that I access from
firefox extension using liveconnect. At the moment Java app expects an
org.w3c.dom.document type. All I can do is pass the nsIDOMDocument to
it as a JSObject and try to use .call() to get more Objects which I
can then convert to strings and get some properties out of them.
I know there has to be a way of accessing nsIDOMDocument methods
straight from Java as if it were a Java class. Do I need to "embed
Mozilla" for these purposes?