Epoxy works best for me. It's the one for underwater repair, yung stick type na pinuputol at minamasa sa mga daliri para ma-mix ang resin at hardener. I'm sure it's available there.
First I get a small piece of base rock where I want to "plant" the frag. Kung sinisipag, I drill a hole using a cordless drill with masonry bit. (actually kahit anong bit puede, malambot naman ang base rock which is "dead" live rock) Then I fill the hole with freshly mixed epoxy, stick the "cutting" into the hole, and shape the epoxy around the base of the coral. Then I usually place this at the bottom of the tank, gradually migrating it higher so it doesn't get shocked by the light. As an option, you can epoxy glue the base rock to your rockwork once you've found it's final resting place.
Another product that works OK is IC Gel, a gelled superglue. That's what they use in Tonga. As I mentioned in another thread, they glue the frags onto nylon bolt heads. Superglue is quicker.