I want to add a new mail address in "Allow sending mail only from these addresses:" but i get this error :

Message: invalid request: zimbraAllowFromAddress may not contain an internal account: nierdz@nierdz.com Error code: service.INVALID_REQUEST Method: [unknown] Details:soap:Sender

I'm using ZCS 8.0.3 and i saw that zimbraAllowFromAddress is only for external account since version 8. Is there a way to bypass this restriction ?
My need is to have the choice beetween multiple internal account when i send an email.

Thanks for any help