Window screen trouble

I am not able to get the best look at your interior molding on your window frame. I have casement windows at my house that have that same lock you show in the photo. On one of  my windows, I went ahead and used the 70-114 "flush" clip to hold the screens in the frame. Take a look at that part to start, along with the list of other replacement clips I placed on this page to see if you could somehow adapt one of these to secure your screens. You may also want to consider our plunger pins that are used to secure screens. Review this list and get back to us with some thoughts.