Four years of war have left hundreds of thousands of refugees
Government and rebel military leaders in the Democratic Republic of the Congo still have to decide on key issues despite agreeing a new draft constitution.
The two sides agreed that an international force would take care of security until a new single unified army was established.
But analysts say that it is not clear who will provide or pay for the international troops, while rebels are still wary of going to the capital, Kinshasa.
But the deal was nearly scuppered by heavy fighting in the north-east, where Uganda forces pushed a small rebel group, the Union of Congolese Patriots (UPC), out of the strategic town of Bunia.
"The neutral force needs to be deployed as speedily as possible and that is the sticky issue," said Henri Boshoff, an analyst at the Pretoria-based Institute for Security Studies.
"The rebels will not go to Kinshasa unless the force was in place and that could take more than 60 to 90 days," he said.
However, DR Congo's ambassador in South Africa Ben Mpoko says the new government could be in place as early as next month.
Government and rebel military commanders will meet next week to discuss integrating their forces, reports the Associated Press news agency.
DR CONGO'S WAR
Seven foreign armies
At least 2 million dead
Disease and abuses widespread
They must agree on a name and command structure for the new army, as well as which language to use.
Lingala is the lingua franca of government-controlled western DR Congo, while Kiswahili is more common in the rebel-dominated east.
The official language is French.
"If we don't integrate the intelligence services, we will end up running parallel services, and we can't have that for one government," said Thomas Nziratimana, the representative of the rebel RCD in South Africa.
The agreements came at a meeting designed to build on the peace deal signed in December.
The plan is for democratic elections to be held in DR Congo in two years time - the first since independence in 1960.
The transitional government would be headed by current President Joseph Kabila and four vice-presidents - two of whom would come from the ranks of the former rebels.
More than two million people are believed to have died as a result of the war which began in 1998, and at one stage dragged in half a dozen foreign armies.