I read that all Vitos have anchor points under the floor. You just have to locate them and drill through the steel flooring. Using a punch to find and make the pilot hole I found best. I found on my Vito W639 Traveliner SWB the rail hole is 215mm from the rear anchor point bolt. Use your rail to locate the rest. Had I known this I need not have lifted the flooring. I found my first anchor hole by deduction and error.