Authors shelves hates comma

Hello there.

I noticed that the latest firmwares (4.4.9344 for my Glo HD, 4.4.9349 for my Aura) allow us to navigate by authors, quite a good option.
But I write my authors using the convention "Lastname, Firstname". And when opening the Authors collection, I've two shelves: Lastname and Firstname.

Is there a way (in a future firmware) to choose on which cararacter we'll split the authors ?
Or does this option exists (hidden) in the Kobo Ereader.conf file ?

Thanks by advance.

Regards