The best I have come up with so far (I am no Arduino expert) is:
//SoftwareSerial mySerial(PIN_THING_RX, PIN_THING_TX);
//SmartThings smartthing(&mySerial, messageCallout); // constructor
SmartThings smartthing(&Serial1, messageCallout); // constructor
In combination with the modified SmartThings Shield lib found here (I updated examples as well)
This also removes the requirement to define a board type in SmartThings.h which is somewhat “magic”. Let the developers define the Serial object and pass that the SmartThings at this stage.
I have tested on a Leondardo but not with a SoftwareSerial case
BTW looks like you guys have some CSS issues with text wrapped in code tages… the text is white. Try selecting the area which looks like a big white space in this message to see what I mean.