after trying the different methods proposed in the thread (and not succeeding), I tried something really stupid that did work! Here it is... maybe it is useful to other people:

1. Connect the monitor using the DVI cable (yes, you won't see anything)

2. Reboot the computer.  I memorized the key strokes to do it (in my case )

3. Enjoy!

When the computer started rebooting, the monitor woke up.

Hope it helps