The bit that holds pads/bonnets is not permanently fixed. The machine has a permanently fixed drive plate covered in velcro (the stiff "hook" half of velcro). The bonnet/pad mounting board and also each other attachment are velcro covered (corresponding "loop" material of velcro) and also have a stud on them which locates into a hole in the drive plate on the machine.
Not sure a car polisher would be any good as it would need to be only 300rpm or so, and have plenty of torque (not how they are designed). Just get a minitex, much better.