It took a few months for my clowns to go to the anemone, but once they did it was like crack to them -- they never left. So, eventually your clowns will go to it.
In the meantime, do all the tank maintenance, coral arranging, etc., you need to do before those clowns bond with the 'nem.
I had the sweetest, best-tempered, most mild-mannered black 'n white Darwins -- until they got their GBTA. Now my little darlins are piranhas when I stick my fingers in their nano.
The pair we had at work a couple years ago would attack me while feeding of all times! Then again, when I cleaned the tank, I had the giant white long-nosed scrubberfish with me! They left that alone.