The Dutch nationals disappeared in the area of El Tarra, near the border with Venezuela.
The gang included Panamanians, Colombians, Cubans, Guatemalans, Mexicans and Venezuelans.
The new deal will be put to Congress rather than a popular vote.
Negotiations between the two sides are continuing in the Cuban capital of Havana.
Simple economics will be one of Colombia's biggest problems as it seeks to eliminate illegal drug production with the help of FARC rebels.
The two sides said they had reached an agreement to end the conflict and build a stable peace.
Bogota agrees compensation deal with rebels for victims of a decades-long civil war.
The two sides could be near a pact on the terms of confinement for ex-combatants who would be tried in special tribunals.
Follows agreement made in September between FARC leader and Colombian president.
The guerrilla rebels and the government agree to drop their uniforms and weapons in a step toward peace.
The guerilla group has invited the Colombian-born Miss Universe to peace talks in Havana.
After Syria, Colombia is the country with the most internally displaced people in the world
The killer guerrillas in Colombia miss their moms -- a chink in their rough-and-tough image that the government is exploiting.