You have installed DidJiX, us version, on your nice external usb hard drive but all your keybaords are AZERTY!
It's just an example because there's a french version of DidJix :-)
You have changed the /root/.bash_profile and /root/.xinitrc but all these changes are lost at reboot!
Yes, it's a live system and these files are, in fact, modified in memory :-(
And you would like to have an xterm started with Mixxx!
I don't know why but why not ;-)
Remember that a second partition was automatically created by DidJiX at the first boot and that it's available through /mnt/Mixxx/Musics...
From Mixxx, switch to the second console with keys and type the following commands.
echo loadkeys fr > /mnt/Mixxx/Musics/.bashrc
echo setxkbmap fr > /mnt/Mixxx/Musics/.xinitrc
echo "xterm &" > /mnt/Mixxx/Musics/.openrc
Now switch back to the first console with keys, quit Mixxx with (not yet french...) keys and restart it with the keys at prompt... It's ok? :-)
Reboot DidJiX... Always ok? :-)