With the LS5000 you do have to stitch.
When I use the Ls5000 for xpan negatives, I use the FM-3 film holder
which I had cut out the spacer {just one}.
You scan one half then the other half and stitch using a stitching software
{I had from a software bundle } or Photoshop.
I now use the LS9000 and wet mount. It is a pain but well worth it,
{you really see what the xpan can do}.