(Adds details, background) By Loucoumane Coulibaly KORHOGO, Ivory Coast, Nov 29 (Reuters) - Ivory Coast government troops and northern rebels will start to disarm by Dec. 22 in a step towards forming a new national army and reuniting the West African country, a mediator said on Thursday. Vincent Zakane, an aide to the foreign minister of Burkina Faso who has been mediating in the dispute, said the New Forces rebels agreed that by the end of January, civil servants should return to the north of the country, which the rebels seized during a brief 2002-2003 civil war. Reading from an agreement signed this week by Ivorian President Laurent Gbagbo and former rebel leader Guillaume Soro in Burkina Faso's capital Ouagadougou, Zakane said the two sides would outline the structure of the new army by Dec. 15. Previous attempts at disarmament have been scuppered by political squabbling. It will be the first major test of a peace deal signed in Ougadougou in March. "Demobilisation of combatants, stockpiling of weapons and the dismantling of militias will start from December 22, 2007, led by the Integrated Command Centre and under the supervision of (U.N. and French) impartial forces," Zakane said. The Integrated Command centre is a mixed force of rebel and government soldiers already deployed in the area that was once the front line of combat in the world's top cocoa grower. This week's deal specified that rebels who were previously in the army would be paid their salaries with arrears going back to the start of the war, overcoming one obstacle to disarmament. Burkinabe Foreign Minister Djibril Bassole met Gbagbo for talks on Wednesday in the northern Ivorian town of Korhogo where the president made only his second visit to the rebel zone since the war, meeting locals and promising prompt elections. Gbagbo appointed rebel leader Soro as his prime minister weeks after the March peace deal and the two men agreed this week to hold elections by mid-2008. The disarmament process calls for forces to gather at allotted sites where they will hand over their weapons to United Nations and French peacekeepers. Soldiers and combatants who meet selection criteria will then be able to enrol in the new national army. Those not selected will be reintegrated into civil society with help to start their own small business or find work, officials say. An 18-month programme is also being planned to provide vocational training for around 40,000 ex-combatants on both sides. The Integrated Command Centre will provide security during the disarmament period with foreign peacekeepers as back-up. Militia groups in the unstable west of the country briefly began to disarm in May this year but the process quickly fell apart amid squabbles over money. (Writing by Peter Murphy; Editing by Daniel Flynn and Giles Elgood)