I did email the creator (Florian) of the Lexicon entry about Sharp Edges, but I guess it went to spam or something.
The way described is just wrong. To simply separate mesh, you mark the correct edges Sharp and you also add an Edge split modifier and untick the Edge Angle option. Now, I don't have Lotus, so I don't know about the export settings, but it's usually either "Apply modifiers on export" so your mesh only changes for the export, or you have to manually apply it and then go one step back.
This way, your mesh stays clean for future edits and you can freely use the Remove doubles function.
Hope this helps. If you need to know more, let me know. Thanks!