Since you keep ignoring my questions on the issue I have nothing to add.
I'm not ignoring your questions Alexey, I'm just too busy these days and can't put my hands on everything I'd like to :( Wait few days, I'll analyze the problem more deeply and then we'll discuss it ;)
And I was not on JBXB-100 watch list before, now I am ;)
Whic XB versions are you using?
There is JBossXBParser interface here http://anonsvn.jboss.org/repos/common/jbossxb/trunk/src/main/java/org/jboss/xb/binding/parser/
which is a SAX-like one. The only implementation is SAX-based.
Since, I guess, when you marshal DOMSource into a String you navigate through DOM structures, you could generate the needed SAX-like events and they will be directly processed by XB. That would be DOM-based implementation of JBossXBParser. I think it shouldn't be a difficult task to do. Do you want to do this?
The problem with the current releases of XB is that there is actually no way to supply an alternative impl of JBossXBParser. But also because of this JBossXBParser interface can be reviewed and simplified safely since there have been only one implementation. So this one is also easy to fix.