Don't you just have the ripped audio tracks converted to mp3 as they are ripped?
Or are you trying to process some .wav files you already have?
Here's how I have it set up:
IN EAC, under EAC->Compression options->External Compression tab, I check the "Use external program for compression" checkbox, choose LAME MP3 Encoder in the "Parameter passing scheme" drop-down box, put in the path to the LAME .exe, put "--r3mix" (no quotes) in the "additional command line options" box, and uncheck "delete WAV after compression" (in case I want to edit the file). I leave the other settings in the other tabs at their default.
And if you want to compress a bunch of .wav files you already have, you can do that using EAC as a frontend. Use Tools->Compress WAVs... to pick the files and then compress them.