Well, first of all you need to bypass a "CRC" check, (that use to be an option in the bypass). Then you need to unpack your files (and make copy's), then edit whatever you want. But if you want to de-activate winhex hacks you just need to change PackIO to 0 (data>shadow.txt>PackIO), (PackIO 1 - hacks off, PackIO 0 - hacks on).
Winhex use to be an old way of hacking, a while ago people used unpacked files (CSV's), but you can read about that after using the search function.