I'm in the UK and have been using Asacol foam enema for years now. I am very surprised that it is still not available in the US. Can't understand why that is...
While most people I know who do use it are quite happy with it, I could never hold it in. I find too much foam comes out even with just 1 squirt. So, I gave up using them and now have boxes of these lying around now as I have gone back to predfoam. The salofalk foam is slighly better than the asacol one but even that caused me problems.
I also found the applicators in the asacol foam had hard sharp edges and they really hurt my ass when I tried to get it in!! At least the predfoam ones are soft but the asacol ones are a nightmare. As if my ass doesn't hurt enough as it is!! lol