My advice is to wait it out. The flow around the anemone shouldn't be a big issue. Make sure it is adequate, but not too strong that the clowns are blown away.
I went to an LFS once that did something called force hosting. Basically they put an anemone and a clownfish in a LARGE bag and slowly drained the water from it. Eventually the clown was absolutely forced to touch the anemone. Afterwhich the clown hosted the anemone. Obviously I wouldn't recommend trying this. It seems very dangerous and inhumane...as a matter of fact, why am I sharing this???
Anyway, good luck. I hope my clowns host one day too. I have a hammer that would look good with a clown on top
It may happen tomorrow, it may happen 8 months from now, or it may not happen at all. In any case, be optimistic. I hope everything works out for you.