I'm also from Belgium (Kortrijk) and faced the same problem.
I hunted down a Freedos (MSDOS-compliant) keyboard driver.
It works very good in Dosbox.
I don't remember were I got it from, so I uploaded it myself.
You can find it at : http://users.pandora.be/frederik.masselus/KEYB_BE.zip
Just unzip the zip file into your Dosbox mounted directory and
add 'keyb be' to the last part of your 'dosbox.conf'.
Or just type it in when starting up Dosbox.
Now you should have Azerty on Dosbox.