I’ve never found a way to emulate the Ins key on a Mac. On my vDosWPMac system I supply a WordPerfect macro that toggles Typeover mode, and I suggest that users assign that macro to a key. I suppose XyWrite has a command that switches or toggles Typeover mode; the best thing would seem to be to assign that macro to a keystroke in Xy. But maybe I’m wrong about this?