Yeah...I've thought about the Yamaha Sub-Kick...but I'm not hurting for low-end THUMP with my current configuration.
And since I have an M/S overhead pair...I jusr blend in the e602 track with the stereo Kit tracks as needed, and I can go from a lighter/distant sounding Kick drum to a huge, fat, THUMPING Kick drum just by pushing the e602 fader up/down in the mix.
Oh...you can't edit/delet yet...I asked the same thing! 
I think the next Forum software upgrade will add some more functionality... 