The short answer is "not in I7". I7 files begin like this
* //IFID// leafname
XML does not. Any file that I7 can read will not pass any XML validation, and no valid XML file will be readable by I7. You might be able to cook something up with I6, however.
More generally, most configuration file formats won't tolerate "garbage" at the beginning.
Also, I7 provides support for "binary" files; I'm not sure if this header applies to them, and if not, XML would hypothetically be possible.
But there's another major roadblock: the only way to grab a file's text is all at once, and that may not be suitable for our purposes.
At any rate, I'd recommend YAML instead of XML since it has stricter rules about where and how whitespace may occur, and is generally simpler.