Why go to the dealer and acquire these additives? Don't you think it would be a great idea to support the efforts of the techs here on the MercedesShop.com site and order these additives through their on line parts shop? Check the Webmaster's post for the part numbers you need. Their prices seem very reasonable and you don't have to pay sales tax.
As for the kerosene, I understand that the manual states that diesel can be winterized through the addition of up to 50% kerosene, I believe. Check your owner's manual to be sure. The kerosene acts to prevent diesel fuel from gelling at low temperatures. As far as using kerosene for any other purpose is concerned, I'm not sure what you hope to achieve. It will not eliminate smoke. The smoke you have is the result of having a slight excess of fuel available for combustion. This slight excess of fuel acts to produce more power. If you reduce the amount of fuel available, you will reduce the amount of power the engine will produce and the car will be sluggish.