Debugging installer does not works as expected

When i want to debug the installer i simply run “ubiquity” in terminal and hope to see any debug data there. But i dont see any reports at the command line. So i tried:
ubiquity --debug

I also dont get anything at an error.

Please check /var/log/installer and /var/log/syslog for debugging output of ubiquity.
See: https://wiki.ubuntu.com/DebuggingUbiquity