You record your DI to a track in ProTools, set the output of that track to say output 3 if it's a mono track, or outputs 3/4 if it's stereo (not sure how ProTools deals with hardware outputs or differentiates between tracks because I don't use it). If the track is stereo make sure you pan it 100% to the left. Connect a cable from the output 3 jack on the back of the 003 into the line level input on the reamping device (Redeye in this case) then connect a cable from the reamp output on the Redeye into the input jack on the amp. Mic it up and set a new track in ProTools to record that mic. Hit record and the DI will play back out of output 3 and into the amp while the new track records what the mic is picking up. Done deal!