Hi,
Just create a new database from the input data with this option turned on.
I've expected db:add to do it. Not important.
If it's not well-formed, you can't store it in BaseX.. If you can do so, it would be an error (and rather surprising to me ;).
Well, the not well-formed is the response for my query for getting the document after I've done what I've described earlier. Maybe this is the reason that the new db does not 'function'. I'll try adding the header lines to each new xml before using db:add.
Cheers, C.