(Recasts with approval of new commission)
HAVANA, June 2 (Reuters) - Cuba's national assembly named former President Raul Castro on Saturday to head the commission charged with carrying out changes to the constitution that would provide legal backing to the island's economic and social opening.
The nomination of Castro, 86, adds to signs that the presidential handover in April to 58-year old Miguel Diaz-Canel does not herald a sweeping change to the island's one-party socialist system, one of the last in the world.
Castro is slated to remain head of the Cuban Communist Party until 2021. The current constitution, adopted in 1976 during the Cold War and amended three times since, calls the party the country's guiding political force - a definition that Castro has said will not change in the rewrite.
"As I said when I took this office last April 19, comrade and army general Raul Castro Ruz will lead the major decisions on the present and future of the nation," Diaz-Canel told the national assembly, which was holding an extraordinary session outside its usual twice-yearly July and December meets.
"Correspondingly, the Council of State proposes that it is he who presides this commission."
The new constitution is expected to include age and term limits for political leaders proposed by Castro and to reflect other changes in society like broader rights for the gay and lesbian community.
"What is coming is an "update" of Cuba's constitution, not the prologue to a "transition" or an otherwise dramatic break," said Michael Bustamante, an assistant professor of Latin American history at Florida International University.
Castro, the brother of former leader Fidel Castro, first announced the need for a new constitution in 2011 after embarking on a series of reforms cautiously opening up the economy to foreign investment and the private sector in order to make Cuban socialism sustainable.
Some clauses in the current constitution, such as one forbidding Cubans from "obtaining income that comes from exploiting the work of others," are at odds with those changes.
"Cuba has to make substantial changes to the constitution that endorse private property, self employment and cooperatives as part of the Cuban economy," said Julio Perez, a political analyst and former news editor at state-run Radio Habana.
The former president's daughter, Mariela Castro, director of the Center of Sexual Education, said in May she is campaigning for it to acknowledge same-sex marriage. The assembly unanimously approved the Council of State's proposals for the 33-member commission, that included party number two and oldguard revolutionary Jose Ramon Machado Ventura, 87. Diaz-Canel will be deputy head of the commission for rewriting the constitution.
Once the constitutional draft is ready, it is slated to be discussed first by the parliament and then by the broader population, before being submitted to a referendum.
Separately at the assembly session, Cuba's government delivered a positive report on a pilot project in the Artemisa and Mayabeque provinces for reform of local government to make it more responsive and state business more efficient.
The assembly passed a motion formally extending that experiment throughout the country, creating the position of vice president within provincial assemblies.
Under the old structure the presidents of the provincial governments were responsible for attending to services such as housing and welfare, garbage collection and taxes and the numerous businesses such as eateries that they run.
The new structure, which was implemented earlier this year, has the president attending to services and popular complaints about them, and the vice president taking care of business. (Reporting by Nelson Acosta, Marc Frank and Sarah Marsh in Havana; editing by Diane Craft)