Start out doing the saw, holding the handsticks in the middle. When the devilstick rolls onto the right handstick take the left handstick out of the saw. Now you need to do one complete flip of the devilstick with only the right handstick. This is the exact same thing as a Propeller, except that the devilstick is in a plane perpendicular with your body (or alternately a One Handed Saw). While the right handstick is flipping the devilstick, do a Baton Flourish with the left handstick. Then insert the left handstick back into the saw.
Here's a video of the trick:
In this variation you don't pull the handstick out of the plane of rotation of the devilstick to do the flourish. But you flourish the handstick through the spinning devilstick, kind of like a gear.
Another, quicker variation, is to do a normal saw with baton flourishes. When the devilstick rolls off of the right handstick onto the left handstick, give the right handstick a quick baton flourish. The slower you can do the saw, the easier it will be to do a full baton flourish. Also, the flatter and more horizontal you can keep the handsticks as they flourish, the better this looks.