Is it possible to modify the XML code from DraftSpace?

I'd like to add the chunk attribute to the XML. I work from a Mac so using DraftSpace makes it easier than having to work thru a virtual machine.

I can see the XML code in DraftSpace but I cannot figure out how to modify it.

Even if I have to download, modify in a text editor and reupload, I'd be fine with that. But I don't see that solution either.