yeah, that has been requested too back when they were released, sucks nothing has been implemented yet. Only way I have been doing it is 1 of 2 ways
call the loop up like in video and then hold platter and needle search to the beginning of track to start mixing
set a loop and set it as one of the A,B or C hot starts, the hot start will save as yellow now instead of green in the button, load track, load loop, play track as normal and when it gets to the part you want to loop, press the saved hot start/lopp you loaded
hoping they can implement something in these decks to do this, I used to love this ability in serato and hate that i have lost it. Maybe in the "out" menu that pulls up after you set a loop then can have a cue back to beginning shortcut or something