Possible lead on converting epub to kepub...

I'm new to eReaders in general and just purchased the Kobo Aura HD. While I was waiting for delivery I downloaded the Kobo Android app on my 1st gen Nexus 7. I noticed that I would only accept epub files and not mobi. Once you load the epub files on to the device, you need to use the app to import them. The process of importing them on the Android seems to create a new file (or directory of files, rather) and the newly imported book acts exactly like a kepub with cover art, ToC, links, chapter progress etc.

The file structure that the Android app creates in it's /kobo directory looks like this:



Which is basically the same exact file name as the files under the /.kobo/kepub/ which are zipped up (without the .zip extension).

Here's what a kepub downloaded from Kobo's store looks like after being extracted:


I tried zipping up the files I extracted from the Android, removing the leading S- and trailing -# and placing it on the Kobo. Unfortunately, the Kobo didn't recognize the file.

I feel like on the right path here, but I'm too tired to keep playing around with it tonight. Maybe someone with more experience could figure it out.

(PS - why would Kobo make the Android app convert epubs to look nice on Androids, but not on devices that we actually paid them money for?)

Cheers,
Sean