Unknown lvalue 'PIDFILE' in section 'Service'

Hi

Today I installed postgresql 9.4 on Lubuntu 15.04 from the
EnterpriseDB's package.

I modified pg_hba.conf to accept connections from the local network, and
tried to start the backend. It do not; looking the log, I can see the
message I copied to the subject. The full log entry is
[/lib/systemd/system/postgresql-9.4.service:12] Unknown lvalue 'PIDFILE'
in section 'Service'

But the corresponding entry in
/lib/systemd/system/postgresql-9.4.service shows
PIDFILE=/opt/PostgreSQL/9.4/data/postmaster.pid which is perfectly
valid, because the
data dir is Environment=PGDATA=/opt/PostgreSQL/9.4/data

What is going wrong?

TIA

Marcelo