Mounting to a wall?

I thinking of purchasing an Asus RT-ac66u, an upgrade from WRT54g. I understand there is no mounting arrangement for putting this router on a wall. This unit will be used as a AP and connected to an internal lan, internet routing will be handled by a different device.

Is there a reason it cannot be mounted on a wall? I have not found any specific information.

If it cannot be wall mounted, is there another relatively flat router that is recommended?

Thanks, jon