I can't map Alt + Prnt Scrn in Synapse 3.

Prnt Scrn requires that I hold Fn + Home and when I try this I get Sys Req which is what I'd get if I pressed Fn + End. I had been able to map Prnt Scrn, Shift + Prnt Scrn and Pause which is Fn + Pg Up. Fn + Pg Dn gives me Ctrl + Break, Shift + Fn + Pg Dn gives me Shift + Ctrl + Break, and Shift + Fn + Alt + Pg Dn gives me Shift + Ctrl + Alt + Break.