I still have the same problem with the latest beta: if Sublime is already running, and I launch it again with the --data option, it'll open a new file with the data folder's name.
Is it a bug or am I doing something wrong?
This is the command I am using with WinSCP:
"X:\PortableApps\Sublime Text\sublimetext.exe" --data "X:\PortableApps\Sublime Text Data" !.!
where !.! is substituted with the complete file path