introducing qi4j into existing apps

• large tutorial for introducing qi4j into an existing application is needed - the proposed step by step for petstore would be good.
• coexisting with spring ?
• coexisting with hibernate ?
• there is "a lot" of good stuff, but perhaps too much to eat at once - how to introduce bit by bit to others while at the same time deliver functionality ?
• would like a possible fallback route if qi4j introduction fails