You need to install the hercules dj mp3 drivers for leopard. Then you have to set up the midi map.
I don't know if a template has been released for Traktor PRO but if not, you'll have to do it from scratch (which i recommend)
Read your manual (eventually read a Traktor DJS3 manual)
Traktor Pro 2.0.3/ Mixmeister Studio 7/
Elitebook 8460p and 8560p, both: i5-2520m /6 Gos RAM /240 GBs SSD/ Windows 7
Denon DN-MC6000 /Behringer DDM4000 /2xDenon DN-S1200
Tascam DR05 /M-Audio Firewire 410 /Hercules Deejay Trim 4&6
Roland MC-909 + MC-307/ Ableton Live Lite/ Renoise 2/ Prodipe 4in/4out