I have been already thinking about such an option. I'll consider if I add it to next version.
My school by default uses a version of ls that doesn't allow showing groups. (SunOS has multiple versions of ls). Anyways, I fixed the error by adding an alias for ls to /usr/bin/ls and disabling alias clearing. I think it would be benificial to have an option to specify the ls command perhaps with the shell options to a specific ls.
btw I think WinSCP is GREAT! and this is just a minor detail. :D