I'm trying to mount a Hampton Bay track light power feed to a standard 4" round ceiling box. The power feed seems to be designed for a ceiling box where the mounting screws make a line at 45° to the walls of the room, but the ceiling box I'm working with has the mounting screws such that the line drawn through the two screws is parallel to one wall. Mounting the power feed using the existing screw holes would result in the track running diagonally in relation to the room walls.
Here is a photo of the guts of the power feed
And here a drawing of the ceiling box with its relationship to the walls
And a tracing of the power feed baseplate in the same orientation as the ceiling box.
And finally, what I imagine a 45° offset crossbar bracket would look like if it existed.
I've tried Home Depot (of course), online searches, and several lighting stores but nobody has anything like this. I found a Westinghouse "universal crossbar" but it provides only about 25° of possible rotation, not nearly enough.
I cannot believe this problem has not come up countless times, both in this context and in many others besides track lighting, and a solution must already exist, but I have not been able to find one.