I despaired of DS' UI and DSON, have been using D3D's $$ DSF Toolbox to export DSF props to OBJ.

Couple of 'gotchas': I've yet to figure how to include morphs, and sometimes is 'non-trivial' to associate textures with materials.

But, to my surprise, you may 'un-pack' DSF or DUF with eg 7zip, then open the 'un-typed' file as 'indented text' with eg Wordpad. DUF files usually hold materials' texture calls near the start...