This is for Sony Ericsson M600,W960,P1 and P990.
Its easy.
1.Extract all
2.Install capswitch
3.Install swissmanager pro (if you swissmanager cant install, try the file explorer or profilmail).
4.Open capswitch and turn 'off' the capabilities.
5.Now open swissmanager or explorer and copy the file ''installserver.exe'' into c:/sys/bin and paste.
6.Restart your phone to make sure the phone refreshed.
Now you can install unsigned applications.