The disillusionment came when trying to put the mounting bracket on the EOS 7D. Unfortunately, the lateral holding arms are shaped so that the flash is down about 20 ° downwards when the bracket is fully inserted into the hot shoe.
The attempt to push the strap only halfway into the hot shoe, so that the holding arms do not touch the folding flash, failed: the lightning lit just not. Apparently, the camera has a mechanical switch in the hot shoe, the internal flash of the disabled as soon as anything is in the hotshoe.
The experiments with my second case, an EOS 50D, struck just fail. This time, expressed not the lateral support arms, but the two plastic fins directly above the flash foot, the flash down. The result is in any case the same. And also the problem of deactivation of the flash by the switch in the hot shoe remains.
So back to the thing. Too Bad.