What's your mounting pole setup consist of?
I use galvanized pipe, 1 1/2 to 2 inch size. Depending on where I plan on driving in the pipe, I may use two threaded 10 foot sections. I drive the first section in to just above water line and then thread on the next section. If it's too tall, I just saw it off 4-6 feet off the water. I use a chunk of 4x4 to protect the threads of the pipe I'm driving. I found out the pipe does deform if you aren't careful, which makes connecting the sections...difficult. :-)
I used pre-drilled angled metal and 2 inch U-bolts to connect the house. The metal is galvanized and has round and slotted holes pre-drilled in it. I cut off two pieces to match the width of the back board on the house. My back boards stick up above and below the level of the house, to make mounting them easier. Then I just marked where some nicely located pre-drilled holes were in the metal and drilled holes for the u-bolts. Couple of washers on each side for strength. The "U" part of the bolt sticks out the back of the nest box backing board, giving you a place to slip it on the pipe. You might not even need the angled metal, but I figured it would last longer with more support.
I'll dig up a picture and post it next chance I get.
Clear as mud, eh?
Found the pictures: