[Forum] Custom User Group Permissions?

[DejanK]

I simply tried to change permissions for the regular members to NOT be able to post in the news forum and I get a pop-up saying custom permissions for this usergroup must be enabled.
How do I enable it?
I don't see any option under the specific user groups settings and when I did a search it says I have to create some xml file.. really???? For something as small as changing permissions?

[Trevor Hannant]

At the top of the page, there should be two radio buttons - select the custom permissions one.