Apparently the Giant Pumpkins are not showing when you use your own Flatbed trailer. I tried both Cargo Market and the Job Dispatcher, but they are invisible. I have the load however as can be seen in the picture. Also switching servers or relogging didnt help.
p.s. the Flatbed trailer in the picture is a Krone trailer. I will try the same thing with a SCS trailer and see if the Pumpkings will show up.