I have NO experience in doing this, but this is what I've read:
Take fairly large cuttings, small ones are likely to die off quickly.
Wash the cuttings in saltwater, as you would do for any other soft coral cutting.
The cuttings are probably most easily attached in a cup with crushed coral or live rock rubble.
I'm not sure about using a cable tie...they'd almost certainly decide to detach when you weren't looking
HTH,
-R