iTunes tab - > directly to external HD (I dont have the P4, but the SC5000s so basicly same work-method)
But that did not let me re-sync back to iTunes (obviously)
So when I began to get my tracks more updated with cues, loops, fixing wrong bpms etc, I then created a copy of the iTunes folders in the ‘Crates’-tab, which allows me to re-sync when I have made changes to the tracks on the players.
But to my knowledge, if the folders and tracks are in this Tab, then you are able to re-sync.
(Sorry, the tab is called ‘Crates’, not ‘Collection’…)