Bypassing the on-board A/D D/A converters

[Kwiz]

Is it possible to bypass the converters on the DM-4800? I want to use an external analog summing box but don't want to add another level of conversion in the process. I was thinking that I might be able to patch the outputs of the summing box into the insert of the 4800 stereo bus but, I'm not sure if that will bypass the on-board Tascam converters.

Thanks