The installer command line arguments changed from SCC 4.1 to 4.2. Refer to SCC's User Manual for complete instructions, but in short:
/HELP, /?
Shows a summary of this information. Ignored if the UseSetupLdr [Setup] section directive was set to no.
/SP-
Disables the 'This will install... Do you wish to continue?' prompt at the beginning of Setup.
/SILENT, /VERYSILENT
Instructs Setup to be silent or very silent. When Setup is silent the wizard and the background window are not displayed but the installation progress window is. When a setup is very silent this installation progress window is not displayed. Everything else is normal so for example error messages during installation are displayed and the startup prompt is (if you haven't disabled it with DisableStartupPrompt or the '/SP-' command line option explained above).