EPUB 3 calibre edited-polished metadata not recognized in app

[homura_no_ko]

Hi folks!

I need advice on a problem I haven't been able to solve for a long time.
I've got EPUB 2 as well as EPUB 3 (differs by publisher) files in my Calibre library.
In there, I edit metadata, embed, polish x2, and save, then I use iTunes to drop the files to my iPad's Marvin 3 reader app.

OK, now here's the problem:

Once I finish editing metadata in Calibre and load the files in the Marvin app, nothing wrong with EPUB 2 metadata, but when it comes to EPUB 3...
Marvin won't show the new metadata in EPUB 3.
To be exact:
Title - shows as edited
Title sort - shows as edited
Author - shows as edited most of the time (sometimes the field lists illustrator, translator, editor, etc. - which I don't need)
Author sort - not correct, shows as 'Name Last Name' but should be 'Last Name, Name'
Series and number - is EMPTY!!! (especially important field to me)

So WHAT exactly should I do so those Author Sort / Series and Number show up as they should?

If possible, write me the exact steps I should make.
...I have Sigil installed if necessary. Though, I'm a total Sigil beginner.

*Polishing I use (selected options):
Polish - update metadata in book files; update the cover; remove a previously inserted book jacket
Modify e-pub - strip Kobo DRM remnants; remove all metadata jackets; update metadata; remove non dc: metadata elements

[kovidgoyal]

Get marvin to support the epub 3 standard properly or stick to epub 2, you cn do an epub to epub conversion in calibre to convert epub 3 to epub 2

[homura_no_ko]

As I don't get how I could get Marvin to support epub 3 metadata,
and I consider converting 3->2 as a last resort.

So, I'd rather like to know how to tweak the metadata?

[PeterT]

Originally Posted by homura_no_ko

As I don't get how I could get Marvin to support epub 3 metadata,
?

I think the idea was to open bug reports / enhancement requests with Marvin support

[JSWolf]

Originally Posted by homura_no_ko

As I don't get how I could get Marvin to support epub 3 metadata,
and I consider converting 3->2 as a last resort.

So, I'd rather like to know how to tweak the metadata?

Marvin does not support ePub 3 metadata.

It seems that support for Marvin has stopped so getting such a major change to be made (IMHO) is not going to happen.