Changed the customNotification to my mail address.
I've used the RefreshTool and restarted the OPBM Process Engine. From the changes above, only the first had any effect in my OER installation. The workflow.xml was loaded without problems (as I can check in the log). After that I started getting log entries from OBPM every 10 minutes (change 1. worked), but no entry was related with any of the other two changes. Those two other changes didn't had any effect in my OER installation: every time I changed metadata in any asset i never got an email (change 3.); every time I changed the name of an asset the tabs Taxonomy and Overview always stayed in "Approved" state.
At this moment I really don't know what am I doing wrong, i don't even know if I am doing something wrong configuring workflow.xml, if I'm expecting some behaviour that's not possible to get, if the problem is from the Workflow side that's not sending the correct events or from the event listener side that's not processing them.