Hi apicici,
I got the font working, but with outline = 1 on bmfont, the outline is barely visible in-game. Increasing to 2 introduce black smudges, which is worse. Maybe some manual editing of the fnt font is needed?
That's what I did to make the outline (and the reason why I said to add the padding), but I created a script to do it for me instead of having to edit manually.
A way to make the outline manually that's easy is to create 8 copies of the font omg, offset by 1 pixel in all directions (including diagonally), make them all black and merge them, then add the original on top.