DOCBOOK-APPS: Suppressing <?xml version="1.0"> added by XMetaL

I'm a newbie, thinking of using XMetaL for DocBook.

One of the things I got stuck with right in the beginning is that XMetaL
adds <?xml version="1.0">  to my chapter files (external entities), even
when opening in "Edit as a partial document" mode. 
And saxon doesn't like it. Can anybody tell, am I doing anything wrong?
I'm going to have lots of files, so removing the line manually is not an
option for me. Sorry if it's offtopic.

Thanks
Tatiana