Apply Hemstitching to a Garment: Applying a hemstitched design to a garment takes a little forethought and planning, but it's not difficult. Kenneth D. King gives you a guide for how and where to apply hemstitching most successfully. | Threads Magazine
The page is in Italian, and the translation Google comes up with is actually pretty comical, but the pictures are enough to give you the gist. One thing that I think may be important is that it's done outside a hoop.