It does sound like you need to learn Spring first to really understand what I am going to say and to integrate with Flex.
But Spring has a BlazeDS integration so that you can use Spring Beans as backing beans in a FLEX form. It is actually really easy, in that it is one entry in your Flex configuration. I remember seeing a 10 minute video online by doing a Google search.
I think it was this one
http://coenraets.org/blog/2009/02/spring-blazeds-integration-on-adobe-tv/
sorry it is an 8 minute 10 seconds video.
Good Luck
Mark