I've noticed a lot of useful modules already created such as workflow, ACL, diff, and more. But these only seem to work with "content types". In our project, we have decided that "content types" aren't really well suited for what we need (Entities make more since). Very complex relationships must be modeled. Our entities are just that, entities, not content.
The problem is that when building an entity using hook_schema() and hook_entity_info(), these entities are not available to be used with different modules such as workflow. Is there any way to make them available? Or will we have to code similar workflow functionality by hand?
Workflow does exactly what we need, except only on content types. We need it to work on entities as well.