> Can someone give me an idea of how to copy a SMD to the opposite side?
You can't. Even if you hand-edit the pcb file it doesn't work.
> My pcb version is 1.6.3 (the latest sable version, according to the
> pcb page).
You need a newer version:
http://sourceforge.net/projects/pcb
With this version, right-click on the part and select "send to other
side".
