On my 1999 SL500 Sport the owners manual has the following info re the soft top storage compartment:
"Raising the soft top manually:
4.Unlock soft top storage compartment lock,located on vehicle right side: Place open-end (tool) wrench on bolt between roll bar and storage compartment cover. Turn (tool) wrench towards rear of car. Open storage compartment cover and place in upright position."

Hope this helps.