Do you mean button names in the game's font?You have to change the font, then use Deling to import it back.Actually, I'm not sure if the PC button names are in the font or if they're just colored text. If they're colored text, you'll have to modify the field files with Deling (it's a massive undertaking. Don't do it).
If you put {x0527} in the text editor it will correctly show □ but it'll be automatically replaced with B1, B2... I was looking for more special characters and I've found some icons from the icon.tex; here's some examples:Replacing a texture icon with the Playstation buttons is possible but non of this icons founded are unused. The icon.tex file countains 2 times the Playstation buttons but I coundn't get those. By the way, you can easily replaced all buttons using the ctrl+f command in Deling. All we need is to look for unused symbols or the extra PS buttons.