2K / 4K External Display resolution MacBook Pro Retina late 2012

Hey Guy´s, I´ve a problem with my MacBook and my new Asus PB287Q external 4K monitor and since I´m really frustrated I´m using this channel.. Following situation:

MacBook Retina 13" late 2012 + Asus PB287Q

Unfortunately after I bought the new 4k screen I noticed that my Macbook is the only retina MacBook which isn´t supporting 4k .. Ok, after the first depression sattelt, Apple website says at least 2k support, so my screen would be at least a bit worthy MacBook Pro (Retina, 13 Zoll, Ende 2012) - Technische Daten

So at least 2560 x 1600 as the support page says.

Now the big question is how? Only mini-display port or also HDMI?

For now I´m trying with HDMI and I can't even choose the resolution setting 2560 x 1600.

But before I gonna buy a Displayport-to-minidisplayport cable I would like to know if its working then and worthy..

Thanks a lot in advance!

Markus