On Sailfish 4.4 this worked for me straight forward as well. But with 4.5 executing
Results in
lxc-attach: aliendalvik: attach.c: get_attach_context: 403 Failed to get init pid
lxc-attach: aliendalvik: attach.c: lxc_attach: 1430 Failed to get attach context
May be it is related to the changed privileges or this notice: https://forum.sailfishos.org/t/two-failed-services-every-time-on-xperia-10/9928/5
Do you have the same problem or is it still working for you?