How to store documents in Documentum?

Can someone provide an overview of how to store signed documents in a document management system like Documentum?  It appears there is no out of the box integration with Documentum like there is with Box and Evernote.   I found this on data retention policies -  https://helpx.adobe.com/sign/using/data-document-retention.html

It says "On-demand Data Retention: With this option, customers can delete documents from Adobe Sign at any time through the Adobe Sign API. This option is typically used when Adobe Sign is integrated into an external system of record such as a Document Management System, Records Management System, HR System etc. where the retention policy is configured and managed within this external system."

But how do you integrate with the Document Management System?   Does that need to be coded through the Adobe Sign API as well?