libcyclades-serial-client doesn't support ioctls. This means that some applications, like gphoto2, doesn't work. A test program can be found here: http://www.cix.co.uk/~mayday/code/modem_rt.c
See also bug 232. (Very nice bug number for a bug about RS-232 redirection :-)
I've implemented basic ioctl support now. gphoto2 works now. The ioctl TIOCMGET is not yet implemented, though.