You don't need to process EVERYTHING externally. You could try just routing the kick, snare and room channels into external Compressors and EQ and then send them to a drumbus together with the overheads and tom mics, which you processed in AD. Disable the FX on AD's Master Channel and process everything on the drumbus to "glue the kit together" again. Works like a charm! For processing Addictive Drums I usually use NastyVCS, which is a free channelstrip with everything you need for drum EQ/Dynamics.
In terms of multiband compression: Download ReaXComp, if you haven't already and bypass all the bands except for the lowest frequencies. Set the low band to about 20hz -150hz and compress that with a release time long enough to make the compressor clamps the lowend down on the fastest parts of the song to make it sound clean and nice (so the gain reduction stays on the same spot in these parts).
This will make the fast parts sound cleaner, while the slow parts will have a big fat lowend (experiment with the settings!).
Hope I helped! Post results, if you try it!
cheers,
Mario
AD is a pain in the ass to set up for metal. Especially the snare. gawd! Guitars are Nick Crows 8505 Lead with guitarhacks impulses.
To me it sounds horrible, the snare is barely audible when the rhythm guitars are playing and the kick just... doesn't sound right. And the tom roll part around 02:35 doesn't sound like a tom roll at all, you can barely hear any of it. 
