Any way to pass additional arguments to rsync?

Is there a way to make Back In Time pass additional arguments to rsync?
I'm having the following problem while backing up to an NTFS USB disk:
[E] Error: rsync: recv_generator: failed to stat "/path/to/somefile": Invalid or incomplete multibyte or wide character (84)

On the net I found that a possible solution would be to specify the option --iconv=CP1252 to rsync.
Is there a way to do this?

I'm using Back In Time 1.0.10 in Linux Mint 16 KDE.