Well, that would also not be very difficult, one small servletfilter would be enough to use the embedded forms ftom the processdefinition in Activiti. But we do not populate the individual fields in the forms from Activiti. We use full messages, something that fits our (and most known) usecases better 😉
The way we store things is to create a kind of 'business archive' (in subversion) that contains the process definition, forms, other mappings, xslt's etc…
Cheers,
Ronald