In 1.4.5, if one would make a custom C service, there are something to do, and I make one with this and it runs well :
1 a executable file, locate at $POS
2 a file with service name $SID that contains $POS in a specific format, put under /usr/share/dbus-1/system-services/
3 a file called $SID under /var/palm/event.d/ that run service at startup.

Now in 2.0, dbus is removed and ls2 is used instead. After reading install script of Preware, I think there are some other to do:
1 the same as above 1#
2 a file with service name $SID that contains $POS in a specific format, put under /var/palm/system-services
3 a file with $SID.json that contains information, put under /var/palm/ls2/roles/prv and /pub
4 the same as above 3#

But I cannot make it work on 2.1. Is there something wrong with these?