The cisco aeronets generally have a metal plate that goes on the bottom, there is also a bracket that attaches to that plate with two screws, it will let it 'hang' on the normal dropped ceiling on those metal bars. What controller did you get to manage it ?
I don't think the i model is a stand alone or SAP like the 1600e-sap which I use. I use a cisco 8 port, 4 ports are poe, $100 POE [Power Over Ethernet] switch to power mine so I only have to run a network cable. that way I don't have to worry about where to plug in the $70 power injector out in some hallway or in the middle of some office.
Just to let you know these cisco ap's are not plug and play. On my 1600e's I had to blue cable them for initial config with an IP, then I could web interface the rest of the config, download the config file and use that as a template for the rest of them but it did take the blue serial cable to get started. The controller based ones can 'find' the ap and configure it though there, the cisco 2504 controller, 5 ap license, is around $800 and it's not even PoE