Ability to copy a service from SaaS to On-Premises when APIcast is self-managed

When copying a service from 3scale SaaS to an On-premises deployment using the toolbox command and APIcast is configured as self-managed gateway:

3scale copy service 12345678 --source=https://<SaaS_provider_key>@<SaaSdomain>-admin.3scale.net --destination=https://<OnPremprovider_key>@3scale-admin.example.com --target_system_name=abcdefg

It outputs the following error:

Error: Service has not been saved. Errors: {"deployment_option"=>["is not included in the list"]}

The problem is that 3scale On-premises doesn't have the self-managed gateway option in the configuration.

A fix for this use case would be needed.