I also have the problem with the scissors-like kick (ARRRGH!) To fix it, I've tried a lot of things. Many of them helped, but the problem proved very persistent.
Surprisingly, the best help I've found was on a thread that didn't even address that directly--Timing of Hip/core and spearing arm. CoachBobW's post was especially helpful. This is the URL: http://www.totalimmersion.net/forum/...eferrerid=9700
There are a lot of different focal points you can use to try to keep hips and shoulders in synch. Rolling like a log, as mentioned in other posts, is a good one. For me, the best one has been a focus on initiating the rotation from the hips. As CoachBobW mentioned in that post, it's easier for the shoulders to rotate than the hips. So, if I focus on moving the hips, the shoulders synch up on their own.
Since reading that post, the scissors-like kick is mostly gone. More importantly, my stroke feels SO much easier and more rhythmic.
Josef--as many others have already mentioned, there are plenty of good things about your stroke. Keep up the good work and buena suerte on your goal.