Tested with Mixxx 1.8.0 on Ubuntu 10.04 and 10.10
Tested with Mixxx 1.8.2 on Ubuntu 11.04
Tested with Mixxx ?.?.? on Ubuntu 11.10

sudo bash
cd /usr/share/mixxx/midi
mkdir old
mv Hercules* old/
wget http://slist.lilotux.net/linux/deejay/mixxx/Hercules-DJ-Control-Steel-scripts.js
wget http://slist.lilotux.net/linux/deejay/mixxx/Hercules%20DJ%20Control%20Steel.midi.xml
exit

History:

I've a Hercules DJ Control Steel, and I've used the RMX files to build 
the files for the Steel.

What I've changed :
- Shift is not used the same way, on Steel keypad goes from 1 to 12
- I switch on the LED when pressing a kill button

For the Effect :

1 : FX on/off     4 : reverse
2 : Hotcue1_set  5 : Hotcue1_goto
3 : Hotcue2_set  6 : Hotcue2_goto

When Shift is selected

7 : Loop in     10 : Loop out
8: Loop exit


I don't really know how to handle the scratch button.
Pitch Bend+/- , I don't know how to interract with the engine.

There are some buttons with no midi message to switch the led on : 
forward/rewind, Load in deck A/B, up/down.

The file are hosted on my web site, don't hesitate to test/comment on this.

http://slist.lilotux.net/linux/deejay/mixxx/


Just copy the 2 files in /usr/share/mixxx/midi/


Steph