I don't think I have a solution for you, but this may help someone else.
I had a similar problem - except that my pedal kept getting stuck under my Horn cabinet as I pressed it, so when I got to the end of a seam, it wouldn't stop!
I tried all sorts of things - wedging books and blocks of wood in the gap etc. - until I eventually hit on the idea of a metal L-shaped book end (a plastic one may work, but more likely to break). I simply placed the pedal on the larger side of the book end and it rests against the frame of my cabinet, but is too tall to slide under - hooray!