You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Kenya

Context:
The new office of the PM will have power and authority to co-ordinate and supervise the functions of the Government and will be occupied by an elected MP who will be the leader of the party or coalition with majority members in Parliament. The world watched Annan and his UN-backed panel and African Union chairman Jakaya Kikwete as they brought together the former rivals to the signing ceremony, beamed live on national TV from the steps of Nairobi's Harambee House. On 29 February 2008, representatives of PNU and ODM began working on the finer details of the power-sharing agreement. Kenyan lawmakers unanimously approved a power-sharing deal 18 March 2008, aimed at salvaging a country usually seen as one of the most stable and prosperous in Africa. The deal brought Kibaki's PNU and Odinga's ODM together and heralded the formation of the grand coalition, in which the two political parties would share power equally.

Question:
When did representatives start working on the finer details of the deal?

29 February 2008