I haven't got a clip of it but I think Matt_H can do it.
There is a description in Donald Grants 'Totally Diabolical'
basically its
pop one diabolo up.
Cross arm trap (diagrams show cross stick trap)
Pop the free diabolo up
un-cross arms to throw the second diabolo (not to high)
catch first diabolo, cross arms over the other way to put it in a stick trap.
catch other diabolo.
Until I checked the book I thought the 2D Mills Mess was an arm trap, throw, sun diabolo to arm trap on the other side then throw and sun back to arm trap, then exit but I can see why the version in the book would be seen as closer to a mills mess.
Seán_