How to setup DKIM with external DNS

Looking at this procedure;

it states that “Only virtual servers that have both the DNS and email features enabled will have DKIM activated…”

My DNS are not handled by my server. The only information I need to create the record in the DNS zone is the public key. Why is that not possible? Any means to address this situation?

Thanks for help

Responding to lmyself: actually, it works.
The notice is misleading: there is no need for the DNS to be set in the BIND serveur
Just use the selector like “2015._domainkey” as subdomain et copy the public key that appears in the DKIM form after removing the quotes and tabs.