How to extract the most flavor out of vanilla beans?
Getting the Vanilla from the bean to the taste bud takes time. While many will advocate the use of fresh vanilla beans (as you have tried), I have always preferred the flavor that is granted from a good vanilla extract. In my opinion it is stronger and better distributed throughout the dish. Whether you buy or make your own extract I think you will get a more consistent and rich flavor that way.

(note: thanks to @rfusca for providing the extract link in a previous question)