merging xml subdocuments

I'm building documents dynamically using a templating system. I would strongly prefer having a single xml document to simplify version control. I see that the spec mentions that this is possible, but is vague on details. What I would like is to have a zip file containing a META-INF directory, a 
manifest.xml, and a document.xml.

Is this possible?

Does the unified file need to have a well-known name?

Can I simply concatenate the three documents together and wrap them in <office:document> tags?