Attachments: Is this a bug or a feature?

Today I've made a disturbing discovery on my Nokia E61: I received an email with an attachment in an exotic format (.rls). I didn't expect the E61 to be able to read it "as is", but it did try, though, associating it with Mobile Office which I was evaluating at that time.

The fatc that Mobile Office wasn't able to open the file didn't surpise me, but I couldn't find where the attachment had been saved, when I wantes to look at the file with other tools. The messaging application just tells me that the file has been saved to the "Docs" folder when selecting the "Save" menu in the attachment menus.

Uninstalling Mobile Office didn't change much, the file is now supposed to be saved in the "Documents" folder, but when I look into that folder (on the phone or memory card, I've tried saving the attachment to both places) with either the builtin file browser or other third party equivalents like Y-browser, I just can't find a trace anywhere of the attachment... Weird!

So is it just me being dense or having bad luck, or is it simply impossible to save an attachment if the file format isn't recognized by the system?