Hi sitti
I'm from Mexico and I use accentuated letters too.
The default NX font (blockfont) doesn't identify accentuated letters and even the degree symbol. But I've used the fonts "hershey-sans" and "iso-1" and they give me no problem, I can write whatever I want in spanish (like: á, ñ, ü, °,etc.)
So, give it a try, may be it could help you