Okay, cool
You mean that I should do the following right?:
1. Stop slave server
2. set archive_command = 'true' in postgresql.conf on the master server
3. restart master server
4. run psql -c "SELECT pg_start_backup('label', true)" on master
5. run rsync -av --exclude postmaster.pid --exclude pg_xlog /var/lib/postgresql/9.2/main/
postgres@192.168.0.2:/var/lib/postgresql/9.2/main/" on master server
6. run psql -c "SELECT pg_stop_backup();" on master server
7. change archive_command back on master
8. restart master
9. start slave
Just to confirm the approach :-)