Need help - Browning FN 22 assembly

I field stripped a Browning FN 22 .32ACP pistol today and can't get it back together. I've placed the barrel into the slide cut out and turned the lugs into the slide recess. Then when I put the slide back on the frame and push it to the rear I can only get the forward notch in the slide over the safety catch if I push in on the grip safety, but if the grip safety is pushed in, the safety will not rotate up into the forward notch in the slide. The only thing that worked for me was NOT to lock the slide using the forward notch. Is that the right way to do it or am I doing something wrong?

Vern