My mistake, I mean't English 3/2.1 Esp 1/2.1 and Fra 2/2.1. I think the 3, 2 and 1 are just the menu numbered item.
You are right. The x/ prefix is the menu choice. If you cannot choose a surround output (e.g. /3.x or better) you will not get surround. Granted, you will hear a little in the center even in stereo mode (no mode is perfect).
Again, see if you can set your DVD player to anything but stereo (the 3 choices you listed were all stereo, but there is probably another menu setting to enable surround).
If not, try a different DVD player.