If You use the Copy Pattern To Track function for a ReDrum and the resulting sound is not the same as when You used the actual patterns, chances are that You have loaded the ReDrum with sounds that are quite long and that these sounds now are not triggered in the same way from the sequencer generated notes as they were in the actual ReDrum pattern. When You copy a pattern to a track, the resulting notes in the track will be 1/32s notes, and since they are now residing in a MIDI environment, they also have note-off messages that might shorten (or choke) the sound from the ReDrum. Open up the sequencer Edit Mode, locate these sounds that are shortened and lengthen the notes for these sounds.