[thundernetbr]

I figure it out how to install it silently using a simple (adapted - borrowed from someone that made it to use with CloneCD , sorry, I don't remember his name... ) .vbs file.

You have to make it all the way to get the files from the installer, as explained for Firefox and Mozilla, and I do use it as the last program to be installed.

Copy, paste and save (in the same folder that you copied your Tbird installation files) as tbird.vbs using any text editor:

Set WshShell = WScript.CreateObject("WScript.Shell")
WshShell.Popup "Don't move the mouse nor press any key!",5," - WARNING - ",48
WshShell.Run ("<YOUR-INSTALLATION-FOLDER-HERE>Setup.exe -ma -ira") 
WScript.Sleep 25000
WshShell.SendKeys "{-}"
WScript.Sleep 1000
WshShell.SendKeys "{TAB}"
WScript.Sleep 1000
WshShell.SendKeys "{ENTER}"
WScript.Quit

Now paste this to your .cmd file (the last one that you use - I have to figure it out how to make it work using RunOnceEx method ):

ECHO Mozilla Thunderbird 0.7.2...
start /wait <THE-SAME-FOLDER-YOU-CHOSE-ABOVE-WITHOUT-QUOTES>tbird.vbs

That's it, hope you can find it useful and also make small changes to your own programs...

EDIT: This isn't working well when using the unattended method, only directly running from the .vbs AFTER installing XP. I'm working on a fix to this, seems to be something related to environment variables, or maybe with the time-related parameters of the VBScript code.