15-070 pivot shoe, cam won't lock

I recently purchased two 15-070 pivot shoes to replace in thermalgard windows. My original shoes appear identical to others posted on this site in terms of design and size. The new shoes fit perfect. However, I cannot seem to be able to operate the locking function by turning the cam a quarter turn as I was able to do on the originals. I assume that the red plastic piece is to be the wedge similar to the steel piece on the original. When I turn the cam on the new shoe, it simply slides right back to the original position and won't stay locked. any advice?

I am having the same problems. I turned it with a flat head screw driver and the red piece seperates from the main body of the pivot shoe. I was able to snap it back in. This pivot shoe seems to not let you lock it with out the two piece construction of the pivot shoe seperating? I would ask you to get one of these(15-070) and try it for your self. A video would be lovely? I can not for the life of me get it to lock without it seperating.