Hickory is just really inappropriate for a crowned belly such as an ELB, especially when put under even more compression due to a bamboo backing. This has been discussed recently (please catch up
in this thread). So your problem with set is due to a design flaw. The bow being too narrow for the chosen woods, or the wrong choice of woods for the desired ELB design. Since this is a laminated bow, it is really difficult to remove the set. You cannot heat belly temper it, since that will cause the glue to fail. So you should not clamp the bow in reflex and put it in an oven. That will kill the bow. You could consider removing (some of) the hickory belly, and replacing it with a more compression strong wood, while clamping the new bow in some reflex. This is quite a rigorous approach, but it's probably the only way to go if you want to remove the set. On the other hand, set has not killed a bow. It just robs some cast, but it may not hurt the bow itself. So if it stays below 3" total, I wouldn't worry for this bow and just call it an experience for your future bows.