I have a thin strip of aluminum that can be easily cut and shaped. I'll take 3" long pieces, bend them into an "L" shape, pop-rivet them to the hollow portion of the router's mounting feet, then screw the whole mess into the ceiling with anchor bolts.
Yes, I finally got around to installing the downstairs router on the ceiling of the apartment below mine.
I found a much simpler way of sticking the router to the ceiling, one that will make most of you a bit crazy.
The router has grillwork for cooling on both the top and bottom. By holding the router up to the light, I saw that there was an area about an inch and a half square where I could see right through the middle of the router. So I drilled right through and fastened the router into the ceiling with a single moly bolt. Works great!
I got someone who knows more about networking than I (that would consist of a subset of about 90% of the total population) to configure the downstairs router. It's connected by Ethernet from one of my ports on the upstairs router, and that's about all I understand about it.
tanstaafl.