I just tried my method and it works, both from CLI and also via tooltype. I used PSI to create and open a 640x512 size screen and Multiview happily jumps onto it. You just have to set the PUBSCREEN=mynewscreen argument. Note here i previously stated SCREEN, but this was not correct.
Also, you must give the screens name, not its title, which might differ.
PUBSCREEN is supposed to get the name of an open screen as argument. So you must open one first. You can do that with PSI (MUI) or the screen manager from the StormC package, for example, or with AREXX i assume.
edited