ORIGINAL: adarbrauner
No option of "limited oversea supply" on.
It looks reasonable to establish a convoy route for resupply.
The manual though, at the supply line tracing paragraph, had not made mention of this, nor have I found elsewhere until now;
And sincerely, i don't know and haven't found yet on the manual explanation about how to establish a convoy route. The only occasion in which convoy creation was mentioned as far as I saw,, was in relation with the need to convoy industrial resources;
in addition, Centuur: why to establish it from Petsamo, wich is not a primary supply source, instead from Helsinky or another German supply port?
Petsamo is just a waypoint, you need to draw the line of supply from your unit back to a primary or secundary supply source according to some rules, depending on weather, land, or sea crossing... they are pretty complex but it's necessary to know them.
But if you trace to a secondary, from there you need to trace to a Primary supply source. For a finnish unit that would be any finish city (not Petsamo, which is only a port but not a city), but there are others beside Helsinki.
I cannot recall if you can use GE supply, however. I guess you can too.