First of all this is the wrong forum for generic XML usage questions. This list is people working on the development of the Xerces parser and should not be addressing either Xerces usage questions or generic XML questions. I'd recommend that you use the comp.text.xml newsgroup though there might be other appropriate forums for those types of questions.
I'm not sure what you mean by "binary" characters? The other respondant's interpreted that to mean binary data, however I think that you might mean characters other than low-order ASCII. Of course, XML and Xerces were designed with internationalization in mind and are defined in terms of Unicode not ASCII. Section 4.1 of the XML spec discusses character entities that allow you to enter characters that you can't type in from your keyboard. Basically where you want to insert a "binary" character enter "&#ddd;" or "&#xhh;" where d is a decimal digit and h is a hex digit and will be expanded by any compliant XML processor (including but not limited to Xerces) to the appropriate character.
