Plugin permission custom role

Hello,

So I’m using the Members plugin to restrict backend functionality and add site-functionality. I installed Gigs Calendar aswell. Now I want the people in the custom role to do nothing but edit their profile and have access to the Gigs Calendar.

Now inside Gigs Calendar there’s a function to set the minimum user level to use the plugin, though these are limited to the standard WordPress levels;

$levels = array(
	'level_0' => __('Subscriber', $gcd),
	'level_1' => __('Contributor', $gcd),
	'level_2' => __('Author', $gcd),
	'level_5' => __('Editor', $gcd),
	'level_8' => __('Administrator', $gcd),
);

Using the Members plugin I created a new role, but it seems to have no level at all, because I manually added all the levels from 0 to 8, but none worked.
Now in the Members plugin there’s a functionality to add custom capabilities. Great, but how do I find out what they are? I found a site saying you’d need the ‘capability_type’ hook, of which I can’t find any…

How, how, how do I set permissions for plugin usage? This isn’t documented anywhere, at all?!
If someone can help, I’d be eternal grateful.