I just tried with Verdana. Ok, it's a little bit messy (12 as a base font is a bit too big), but it works great. I tried to find the bits of the solution everywhere. A guy sent me a CSS, but I put the font into Data/fonts in root of my PRS-600. Here I found the right path and altogether, it's great!
P.S. Here I found that the directories and the font names are case sensitive.
Tx