You also can import XML, although I have not fully tested this and I was getting error messages when I re-imported (the previously exported XML file) about undeclared entities but they seemed to be there at first glance. Anyhow, here is basically what you have to do:
<!DOCTYPE Stepbystep SYSTEM "/home/schneide/xml/dtd/Stepbystep.dtd">
As you would, say a Word File:
Menu: File -> Open [ enter your XML document ]
Now compare
You will notice that some things are wrong or missing, e.g. crossreferences. I don't know yet if a complete round-trip without loss is possible for simple (no frills, no nothing added from Framemaker) XML. It makes sense to investigate if you collaboratively work on some text and some guys prefer to work with a plain structure editor (I need some time to investigate this) .
I have just found (from M.Carr) out that there is an XML plug-in (not installed yet):
http://partners.adobe.com/asn/developer/framefdk/fdk.html