Hiya

It is going to be a little hard to attached a new Case directly to a workflow using the REST API.

We still need to extend the REST API services to cover Workflow Control.  The problem for the REST API is pretty much the same as we face for the SOAP webservices (+) Workflow and Web Services - Sage CRM Hints, Tips and Tricks - Sage CRM - Sage City Community

The essential problem is that the link between workflow and an entity is done via the workflowinstance table.  The field case_workflowid is a foreign key value pointing to a record in the workflowinstance table that is an child of the workflow.

You would need to create the case record, then create a workflowinstance record, linked to the target workflow to be followed and then update the case record with the workflowinstance id.  

How would I create a new workflowinstance record using the REST API?

The workflowinstance table (along with all the other tables used to define a workflow) is defined in metadata as a hidden system table.  This means that it doesn't show up in the customisation area.  See:  custom_tables and the values of bord_hidden and bord_sdataaccess.

Are you familiar with making direct changes in meta data? 

Are we able to do this through the REST API? I don't have direct access to the DB.

No.  The alternative would be to edit an existing Case Workflow to have a transition rule that is designed to attach Cases added via the REST API to the chosen workflow.     

Are you to walk me through it? I tried, but couldn't figure it out.

Have a look at the default Opportunity Workflow.  You will see that it has both a Primary Workflow Rule (that manages the creation of the Opportunity from scratch) and Transition Rules (Accept/Reject) that work with records that have been converted from a Lead.

Excellent. Will give this a try. Thank you.