Lebanese Foreign Minister Mahmud Hammud on Sunday said the joint military commission would set the "duration, time and location in these matters".
He made the remarks after meeting UN envoy Terje Roed-Larsen in Beirut, a day after Roed-Larsen had visited Syrian President Bashar al-Asad.
It was the first definitive word on when Syria would fix a date for full withdrawal. Roed-Larsen indicated he had extracted a timetable for full withdrawal from al-Asad during their meeting on Sunday but would not reveal it until he had met UN Secretary-General Kofi Annan in New York this week.
"We discussed all issues related to Security Council Resolution 1559 and its implementation, and I am very glad to say that I think the foreign minister and myself ... see eye to eye on all issues," Roed-Larsen said after his meeting in Lebanon.
Al-Asad had told his parliament on 5 March that Syria's 14,000 troops would be redeployed to Lebanon's eastern Bekaa Valley by 31 March, but a complete withdrawal would be deferred until after later negotiations.
Crossing the border
A senior Lebanese army officer said on Sunday that about 4000 Syrian soldiers had crossed the border into Syria since the troop pullout began on Tuesday.
"Another 4000 soldiers in Lebanon's central mountains have redeployed to the Bekaa region. This is in addition to 6000 troops already stationed in the Bekaa," the military official said.
He said the fate of the 10,000 troops remaining in the Bekaa would be discussed at the military commission.
"The commission will present proposals to the Lebanese and Syrian governments about the status of Syrian forces redeployed in the Bekaa and define these forces' relationship with local authorities," the official said.