I have recently acquired a Metz 3000C m1 Cable and 3802 SCA adapter to use with my 45CL4 flash. The instructions state that the 3802 must be slid into the 3000C cable until the catch engages. I can't seem to push it to this extent unless I remove a small strip of plastic on the underside of the cable device. When I do so, it fits perfectly. Is this normal? Where do I find reference to it? The plastic strip does seem to be made to clip in and out although I only discovered this by close examination.