B-Model instructions for the 8063 (Tractor with Trailer) are now available online from LEGO website.
You may download them at the TECHNIC Downloads webpage for B-Models.
8063 Tractor, B-Model features a 'Sowing Machine' and building instructions are divided into 2 files which you may download directly, from the links below.
Obviously they just include instructions for the trailer. Enjoy!
Thanks Junkstyle Gio for let us know.