Hi,

I explored mozilla's source code to find out how the installer works. I eventually came across the NSIS source file for Thunderbird and the function .onInit can read a INI file with the unattended parameters. So here's mine:

CODE
[Install]
InstallDirectoryName="Internet\Mozilla Thunderbird"
QuickLaunchShortcut=false
DesktopShortcut=true
StartMenuShortcuts=true
StartMenuDirectoryName="Internet\Mozilla Thunderbird"

; More info here:
; http://lxr.mozilla.org/mozilla/source/mail/installer/windows/nsis/installer.nsi#986


Launch it using:
CODE
"Thunderbird Setup 2.0 Beta 1"  /INI="C:\setups\thunderbird\config.ini"


Please note that the full path to the ini file must be passed. I use an auto-it script which looks like this:
CODE
$Version = "2.0 Beta 1"
$Setup = "Thunderbird Setup" & " " & $Version & ".exe"
$ConfigFile = "config.ini"
RunWait($setup & ' ' & '/INI="' & @ScriptDir & "\" & $ConfigFile & '"', @ScriptDir)


This works for Firefox 2.0 and Thunderbird 2.0 Beta 1 (and newer).

The Installer source code:
Firefox
Thunderbird

You do not need to use the old -ms switch (it's deprecated and it won't work with the INI file), when the installer loads the INI file, it enters silent mode.