I *think* you may have to rip that lip off. (remember that saying?
)
Maybe try putting the brackets on the lip first and see if that stands a chance? If I can take any more pictures for you, let me know - they're two different cabinets, so apart from the distance between the brackets and the relationship to the pins on the cradle, I'm not sure what to send you, but if you think of anything that will help, let me know.
