Placing a steel disk inside a non-ferrous pan using an inductive stove
The usual approach would be to put the steel disk under the pot. Such disks are even produced commercially for this purpose: look for an induction interface disk. The basic mechanism is straight forward. The disk heats due to electromagnetic induction; then heat moves from the disk to the cooking vessel via conduction. As long as your cooking vessel is a good conductor and the bottom of the pan is in direct contact with the disk, it will heat up relatively efficiently.

Putting the disk inside the cooking vessel seems iffy. If your cooking vessel has a thick bottom, then the disk will be further from the stove-top. Because the magnetic field strength decreases with distance, induction would be less efficient. Also, if the disk is inside the vessel, it will come into contact with the food and probably need to be washed. Putting it under the pot leaves one fewer item to wash.