The rock I have them on, breaks pretty easy.
Then I just glue the rock to something else.
Otherwise, I generally try to chip a bit of rock with the polyps.
If I use the "scraping" method, I don't use glue.
I just pin it to a rock, and let them attach themselves.
They attach in a week or 2.
Edit: the in the picture, you can't see the rock they're sitting on.
Then the 2 rocks are glue together
Edit #2:
http://www.bareefers.org/discussion/index.php?topic=1618.0