I am developing an application that re-hosting the workflow designer to allow the business analysts to create the processes definitions, then the application will let the user to initiate instances of these processes.

My questions are:

1. How could I store these definitions and where ( database, files????!! ( note that the user will interact with the application by using web)

2. I want to create custom activities for specific business field. Theses activities should be loaded in the activities toolbox instead of the WF default activities. The problem is that I don't know how to load these activities??

I am beginner in the workflow foundation area, and I really need your help in these problems :(??

Thanks