Custom signing workflows on a library template that works via our SalesForce integration?

Hello!

My company is interested in setting up some custom signing workflows. However, all of our reps interact with Adobe only via the SalesForce integration. The tutorial on custom signing workflows only show how to inititate an agreement with a custom signing workflow if you're working straight out of the Adobe EchoSign console.

Is there a way I can program a library template document to be sent via the SalesForce integration but have it go through a custom signing workflow? If so, how do I set this up?

Example:
1.) Document gets sent by the rep to the customer *from the SalesForce integration*.
2.) Customer signs it.
3.) Document arrives back at an approver who reviews it before sending it to the final signer on our side.
4.) Final signer gets the document and signs and then it files as usual.

Thanks so much for any insight anyone may have.