yes its possible but it requires more than just running a fuel line to a can of oil. Vegetable oil or VO needs to be heated so the viscosity of the oil can be reduced to flow through the fuel lines and out of the injectors. the heat of the oil aslo plays a big role in atomization of the VO so it can burn properly, usually there is a two tank setup one with VO and one with Diesel. the Diesel is used on start up to warm the engine and use that engine heat to warm the oil, shut off is also run on diesel to clean the lines of the VO and ensure easy starting next time around.
i dont own a M-B myself yet but im on the hunt for a clean inexpensive 300TD to do the convesrion. i figure if i also add propane injection i can have a fairly quick nece looking and luxurious Mercedes thats almost 100% "green" check out
www.greasecar.com
-cheers
(sorry didnt realize when i posted this was an old thread and therefore old news.)