A bee problem

Bees of some sort (yellowjackets probably) have built a nest entirely inside the eaves at the corner of my house, and when I say entirely inside, I mean you can't see any sign of the nest whatsoever except for all the bees going in and out.

I had a couple of half-empty cans of bee nest spray, which have worked for me in the past, so I gave that a try; however, with the cans half-empty I didn't get as much range as I expected so much of the spray didn't hit the eaves and what did wasn't anywhere near enough.

So I bought a full can and then unloaded it entirely into the eaves, completely soaking the whole area. For a few hours afterwards, there was a frantically large amount of bee activity around the nest. But this morning, I find the bees are back to business as usual. I guess I can't get enough of the spray into the eaves through the drainage holes to do the job; most of it was wasted on the walls, I suppose.

So how do I deal with the bees now? I can't very well get up there to open up the eaves (assuming I can even figure out how to do so) and spray from up close, at least not without a bee suit. I don't see any other way, though. Is this situation dire enough to require paying a professional, or is there a trick I'm not thinking of?