Thanks! The basket is the Wald 137. It was meant to mount to the axle and the handlebars, but I wanted to come up with something that works well with drop bars. So, I removed the two brackets from the top rail of the basket, and hammered one into a shape that I could run from the bottom of the basket to the front brake bolt.

At first I tried using the brake bolt mounted reflector bracket, which came pretty close to a good fit, but this really did the trick.