How to config start/stop scripts in a different data dir for CentOS7/systemctl/PG9.6

Hi,

I do these steps to config Postgresql 9.6 in CentOS 6.x using a
different data directory:
yum -y install postgresql96-server postgresql96-contrib pg_top96
chkconfig postgresql-9.6 on
service postgresql-9.6 initdb
service postgresql-9.6 start
echo "localhost:5432:*:postgres:mypass" > ~/.pgpass
chmod 0600 ~/.pgpass
echo "localhost:5432:*:postgres:mypass" > ~postgres/.pgpass
chmod 0600 ~postgres/.pgpass
chown postgres.postgres ~postgres/.pgpass
su - postgres
psql -U postgres -c "ALTER USER postgres WITH PASSWORD 'mypass';"
exit
#------------------------------------- => my data dir is /sistemas/sat4/bdpg
service postgresql-9.6 stop
cd /etc/rc.d/init.d
ln postgresql-9.6 pgsat
cd /etc/sysconfig/pgsql
echo "PGDATA=/sistemas/sat4/bdpg" > pgsat
mkdir /sistemas/sat4/bdpg
chown postgres.postgres /sistemas/sat4/bdpg
chmod 700 /sistemas/sat4/bdpg
su - postgres
/usr/pgsql-9.6/bin/initdb -D /sistemas/sat4/bdpg
/usr/pgsql-9.6/bin/pg_ctl -D /sistemas/sat4/bdpg -l logfile start
sleep 5000
psql -U postgres -c "ALTER USER postgres WITH PASSWORD 'mypass';"
exit
#-------------------------------------
su - postgres
/usr/pgsql-9.6/bin/pg_ctl -D /sistemas/sat4/bdpg -l logfile stop
exit
service pgsat start
chkconfig --add pgsat
chkconfig pgsat on
chkconfig postgresql-9.6 off
#-------------------------------------

But now CentOS7 uses the new systemd service control system.
I only get to start PG manually like this:
su - postgres
/usr/pgsql-9.6/bin/pg_ctl -D /sistemas/sat4/bdpg -l logfile start