change back my MU install from a naked domain to a "full" one :P

Hey team,

so it's pretty clear I think... I installed my MU to a naked domain, and after reading through some articles here in WPMUDEV and in some other places, I've found out that I'm better off having the www in my domain....

The thing is I've browsed both here and on the net in general, and don't find any walk through that can help me out. I've seen a couple of articles here that point to the General Settings URL settings fields, but those do not show up on my install at least...

Please don't laugh about the following: I've tried to change the install URL through the softaculous panel, which lets you edit the URL, and it worked, but back in WP the url still shows without the www. What's more, in the wp-config file the url is defined as naked, so I modify it to prepend the www, but then when trying to log back in to WP I get constantly redirected to the login...

Sorry for this messy bit of info, I am a bit lost right now, hope you can help me sort this out.

Cheers