500N, I think I've seen more than one comminuque from the UN about Child Soldiers since the 90's ... not all stories, and not all utterances, can cover all topics.
Security Council Tightens Sanctions Regime on Somalia, Eritrea, Extending Mandate of Monitoring Group for 12 Months
One example.
See also UNSC resolution 1261 of the year 1999, seen here in .pdf format.
http://www.undemocracy.com/S-RES-1261(1999).pdf
If you be interested, you can also look into UNSCR 1314.
That said, Courtney seems to be right about what is and can be done about that state of affairs: beyond a harshly worded letter, mostly BFA.