I come back to you to give you news. Strange fact it seems that for installation and execution, if I flow through the USB port in front of the server.
I tried to connect the SSD on the front and the USB key on the back, the bootable key was not recognized
So when installing OMV on the SSD the USB key on the front panel and the SSD on the rear panel works, once the installation is finished, I need to connect the SSD on the front for it to be recognized.
My concern is solved, but I do not understand why I have to go through the USB port in front.