how can we run acme-sac from gdm/wdm/xdm? (acme-sac as window manager)

[nitrofurano]

recently i got to know it is possible to run acme-sac as Linux window
manager, but i can't do it

i tried to create /usr/share/xsessions/acme.desktop

and tried to have:

[Desktop Entry]
Name=acme
Exec=/opt/acme-sac/bin/emu -r /opt/acme-sac -Cr8g8b8a8
Terminal=False
TryExec=/opt/acme-sac/bin/emu -r /opt/acme-sac -Cr8g8b8a8
Type=Application
[Window Manager]
SessionManaged=true

and the acme didn't appear on gdm (only tried on gdm)

later i tried to edit it to:

guest@macbook:/usr/share/xsessions$ cat acme.desktop
[Desktop Entry]
Name=acme
Exec=/usr/bin/acme
Terminal=False
TryExec=/usr/bin/acme
Type=Application
[Window Manager]
SessionManaged=true

since i created a /usr/bin/acme text file with:

bash /opt/acme-sac/bin/emu -r /opt/acme-sac -Cr8g8b8a8

now acme appeared at gdm window managers list, but when trying to run
it, it loops back to gdm login again

what is wrong or missing, which causes this situation, and which steps
i must follow to have acme-sac running as window manager?

thanks!
p