You should be able to use a BTA20, as long as you make the proper adjustments to the circuit to safely carry the additional current. Larger traces, wider trace spacing, etc. As always, give yourself extra space around the components and traces, and once it's all working, I would suggest coating the solder side of your board with a protectant, such as silicone or epoxy. This makes repair difficult to impossible, but also makes the thing much safer in the work environment.
--Tesla