Either listen ..
You do NOT need a plugin at all
The Transmission daemon is completely contained inside the package "transmission", once installed, it gets started in boot, stopped on reboot/shutdown, etc. pp.
... or wait ...
I've uploaded a fixed plugin today, where the plugin does nothing more than to execute
/etc/init.d/transmission-daemon start
/etc/init.d/transmission-daemon stop
/etc/init.d/transmission-daemon restart
/etc/init.d/transmission-daemon enable
/etc/init.d/transmission-daemon disable
actions from E2 menu.
The login of the transmission daemon is "root" and the password is "enigma2".