BERLIN — It’s official. Italy’s Fininvest, Saudi Prince Al Waleed and the Gotham-based merchant bank Lehman Brothers now hold 3.1% stakes in the Munich-based Kirch Group’s core holding KirchMedia.Contracts were signed Wednesday for the transaction, which was announced in March this year. The partners paid DM375 million ($198 million) each for their respective stakes. Each is entitled to one seat on the six-body advisory committee. Fininvest president Claudio Sposito represents his company, Mustafa L. Al-Hejailan reps Al Waleed, and Robert Millard will act on behalf of Lehman Brothers.