How to add attachments to Published KB Articles using delivered Attachments API

We are trying to leverage the out of the box attachment APIs ("Attachment API" or "CSM Attachment API") to post attachment files to Knowledge Articles.  Some details about our setup:

• Knowledge versioning is turned ON
• ACLs are blocking changes to Knowledge Articles that are in Published state
• We use custom KB article template tables that extend Knowledge (kb_knowledge) and inherit the ACL rules of Knowledge
• Instance is on Utah release

By what I understand, the behavior we're seeing is expected as the checkout process is required to edit an article after it has been published.  Has anyone had experience with using the out of the box APIs to post attachments to articles that have been published?

We're hoping to avoid using a Scripted API solution if possible.  We have tried to use a before business rule to capture changes to the attachments table but ACLs appear to trigger ahead of the business rule, blocking the rule from ever running.  Is this possible?

Screenshots of the API errors we receive when posting to a published article.  Thank you!