For an enterprise account, what is the recommended way of creating a distribution certificate? If I look at the distribution tab in the iOS Provisioning Portal, I see this this disclaimer at the top:
Important: Xcode is the preferred method for requesting and automatically installing this certificate. Before proceeding, read Tools Workflow Guide for iOS.
I don't see anything in that guide that discusses enterprise distribution or how Xcode would generate and submit a CSR for you.
I can certainly create and submit a CSR manually, but if Xcode now handles this sort of thing I'd prefer to do it that way.
XCode will do it for you automatically when you create a new provisioning profile, assuming a valid certificate doesn't exist already.
If you go into the XCode Organizer you should see a 'New' button at the bottom of the window (next to 'Import' and 'Export').
When you select 'New' you'll be asked for your developer account details - if you don't have existing certificates installed on your machine XCode will ask if it should request new ones. The process is the same for distribution certificates - however, the account you use to log-in via XCode must be a team distributor.
This is all very well and good, but as per Apple's documentation:
Xcode does not download distribution provisioning profiles. You must download distribution provisioning profiles through your web browser and drag them to the Xcode icon in the Dock.
So while it's quite useful for development it's not so useful for distribution: you can certainly request the certificates in XCode, but you're still going to have to go to the provisioning portal to download the profiles!