Hi,
Here's the article that shows you how to solder RXD/TXD/GND in Ben Nanonote.
http://downloads.qi-hardware.com/hardware/qi_lb60/report/soldering/soldering_on_test_points.pdf
The original design of serial console test points is not for permanent purpose but would be useful for debug or so.
With it, may help you can get all related soldering background as possible. For your reference.
Thanks,
Adam

P.S.: sorry about this, I should post it on wiki but I am a new on learning it.