How to "sign" or "valid" a custom map like Blizzard does?

Hello everyone,

I've been wandering around in the shoes of a guest but now as a member.
Though I'm coming up with a question I would love to know the answer of if anyone knows it.

I am currently trying to "sign" custom maps as Blizzard maps.
This is needed for using them in certain parts on battle.net.

If someone is familiar about how to sign a map, please let me know since I have been searching a lot about how to do it.
Please not that just saving a custom map with the World Editor is not enough.

Thanks in advance, happy gaming.