Don’t bother yesterday I found the answer 
For future helper seekers:
I created a custom Pin Factory and registered it in my module.
Then I created a static TMap which stores the Pointer of the SGraphPin and the UEdGraphPin.
static TMap<UEdGraphPin*, SGraphPin> PinMap;
This Map will be filled in the CreatePin Method, where every Pin HAS to be created with a given UEdGraphPin as an argument
Cheers 