I have created an External Account with the bellow configuration:
And an agency delivery with the previous External Account assigned:
Thank you in advance.
Finally, we had to make the development through a JS activity in a workflow, after a delivery activity. Maybe in the future we try again to do it through a Connector.
Following up, have you been able to get some help with this?
Ok, thank you for your recommendation.
I'm sorry this is far beyond my knowledge. If you aren't able to find help here, I can recommend to get in touch with our consulting team, who may be more experienced with this type of custom implementations.
Also, let us know if you managed to make it work.