I converted a OO writer document into epub2 with Writer2epub. The document has endnotes which are now correctly in the epub (I’ve changed the style a little with Sigil).
Ofcourse every device/app deals with endnotes in a different way: My Kobo Glo shows a pop-up. iBooks switches to a screen where all the endnotes are listed. ADE switches to a screen with just the specific endnote. Calibre reader show the endnote at the bottom of the app.
I didn’t find the right solution from the internet.