ok, the short version: download grfcodec, decode the ecs extension, and look for a line containing ""PASSCOALMAIL"
this is the cargo translation table, containing the 4-letter codes of each cargo. you have to find out which PBI cargos do not appear in this list, and replace a code that is similar
then you need to go through the lines that follow, and replace the lines that look like:
nn*10 00 01 01 xx 1D yy yy yy yy
the y-part is the bitmask for which entry of the above cargo translation table is loaded. the xx part is the ID of the vehicle that is modified. you can compare that with the list from the DBSet readme
You might not exactly be interested in Ferion
, but if you are, have fun