Setting up email send node from the Dashboard (dynamic credentials)

This isn't really a Dashboard question (just involves the Dashboard), so I'll post in General:

If we disregard the actual advisability of entering an email address and its password into a dashboard (that's its own issue), is there technically a way to get email credentials into the email node (and thereby into the credentials file) via the Dashboard/the msg object?

I've been experimenting a little with making flows that edit themselves (create a backup of the flows file, edit the flows file itself, and restart Node Red). So, I'm willing to go a little deeper than just passing the email node a "msg.from" and "msg.password", which obviously doesn't work (I tried anyway). However, I assume one does not simply edit the credentials file, since things in it are hashed...? Again, advisability aside...

Any ideas?