Thanks to you all, I have been working at it today;
I checked the voltage at the alternator, while engine is on, and it shows the same voltage (25,5) as my battery bank...so no charge coming from the alternator...
Will check again the connections on the alternator, and on the relay mounted on the main engine.
Tried 2500 RPM also, and did not get it alive.
Still no light in the red bulb, on the 24 V panel.
Will update once I get it to work.
Not sure if my alternator is the Leece Neville, looks nothing like the pictures on the website.
I got a picture of my alternator and put it on dropbox;