Enable the ability for users to add other email accounts

I have Centrify pushing out an Exchange Email auto config, which works just fine.

One the iPhone however, the ability to add other accounts seems to be locked down. I do not see a setting in any of the iOS configuration settings that would "enable" or "disable" adding more email accounts.

How can I allow through MDM policy the ability to allow users to add other email accounts?

Slamdance