1. You can expose the web designer in the standalone editor (look @ this blog for more info: and a sample seam2 app: http://blog.athico.com/2011/04/using-oryx-designer-and-guvnor-in-your.html ). Note that you have to have Guvnor running somewhere. You can get the uuid of your process asset at which point you could query Guvnor (via its rest api) to get the stored BPMN2 of your process (after user saves it) and store it in your own DB if you want. Designer however right now can only read processes that are stored in Guvnor JCR. Being able to store in a DB would be a nice contribution ;)
2. Are you planning to run in the jBPM Console? If this is your own app, upon your event you could just use the Guvnor REST api again to get the BPMN2 of the process definition stored in Guvnor and go from there.
Hope this helps.