TLC5940 with Arduino MEGA and Ethernet Shield hack

Hello,

I have a MEGA with a hacked Ethernet Shield, for my projekt I want to add a TLC5940 in order to get 12 bit PWM to drive some analog gauges. I can get the TLC5940 working with the MEGA but not in combination with the Ethernet Shield. I know it is possible to combine the Ethernet Shield with the TLC5940 using the Duemilanove.

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1257363045

Is it possible to translate this HOWTO to the MEGA version, I tried tracing the pins used on the Duemilanove back to the MEGA but they seem to be rather different. (I'm not really a genius when it comes to the internals of the processors). I would be glad if someone could point me in the right direction. I searched the forums but only found this tread which ends in a dead end.

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1243928322