My favorite recipe for planting moss is using the buttermilk as well as a bit of fish emulsion (sold at greenhouse stores). Fish emulsion is potent stuff, so use only maybe a few pea-sized globs. Stinky, but the moss loves it! It would even be a good idea to 'paint' some of the fish emulsion onto the wood where the moss mix will be put down. Driftwood may not have a lot of nutrition for the moss to use, so giving it a boost will help. They say you can use some sort of school glue to glue it on the wood, but when it comes to using it with animals, I don't like it. If you're worried about it coming off while it's settling in, I've used rice paper (craft stores sell it) and wrapped it around the moss and wood, then use something like twine to tie it down loosely. Misting the paper with water will wet it down, and light should be able to pass through the wet paper enough to help it grow. This takes a little more work, so you can skip it if you prefer.
When the moss is established, giving it a misting of some well-diluted fish emulsion will keep it going.
Note, when you use the fish emulsion mist, you will want to do this OUTSIDE the tank and let the mist seep in and work a bit. Then give it a gentle rinsing to get out any extra residue. Otherwise it may make the tank water a little smelly. Or, you can skip the misting altogether to be safe. Just a personal preference.
I'll be sure to do that 