From memory ( as I am not on the road any longer)
-Must enable Call Logging
-Also look for Call Log Pool
You need to add some to that set.
The KSU allows about about 250 logs as a whole
Example if the pool has 250 entries then add 20 to that set, this leaves 230 for other sets you may add down the road.
Look under Sets/XXX/Telco Features as a start