ther is a easy way to check, whether your f:ajax is fired: Just remove the render-Tag and put a alert('') into your oncomplete.
As soon your bean is within some context (app/session/request) it will be found by the JSF framework. Have you tried to debug your code, setting breakpoints to your constructor and the setter to check, whether input is passed to the bean?
or F12 (Scripts/Console) in IE.
I don't think you'll get far with request scoped when using ajax, there is some discussion here:
http://community.jboss.org/message/591512#591512 thay me be of interest.