Call DL and ask them. If they say yes AND several people say they've done it, then *maybe* you can believe it.
Personally I don't believe it. WDW and DL sell different types of passes with different rate structures, and the WDW ones say nothing about being usable at DL. Furthermore the "days" on a hopper pass are not stored on the pass itself but rather in the WDW computer system. Unless the WDW and DL computer systems use the same database (which I really doubt), your passes won't be recognized at DL.