Javira: whatever you want, f.ex "menu" or "inbetween", you can see it on chartboost later
outcast: yes, that's the icon of the orginal extension found here which should work! did you also include the frameworks? scroll down on https://help.chartboost.com/documentation/ios to see how, it's also possible to just follow those instructions instead of using any extension or events in MMF at all. (but then you can't specify when to show an ad, it will always just show on application launch)
if anyone works on a new/updated extension, i got a complaint from chartboost about the install call being sent too often (every start of frame instead of launch), probably nothing to worry about (still earning money), but it should be fixed in a future extension.