I looked up the hardware and specs of the two devices. Both can talk CAN but the AEM claims to only support their AEMnet devices over the CAN bus. Since they also make a EGT sensor I suspect they are only interested in supporting theirs. It even states this in the pdf install guide.

The good news is that the EGT to CAN module says it has configurable message id capability. With this you may be able to use one of the AEMnet message id's. The one for their EGT sensor would be best I suspect. You will have to find a way to get the correct message id to duplicate but there may be a chance it would work.