ST-LINK is serial communication possible?
OK, The way to achieve communication in Atollic TrueStudio for ARM Lite (yes it works under lite wersion since 3.0):


Enable Serial Wire Viewer in active debug configuration
Show SWV Console (under Debug prespective)
Open Serial Wire Viewer settings (first button in SWV Console window)
Enable ITM Stimulus Port 0
Enable Start/Stop Trace button in SWV Console (second button)
Use ITM_SendChar function
Enjoy debugging strings!