Disable "File Download - Some files may be harmful..."

[Theo]

I am creating some auto installer scripts for windows 2003. One of the snags I am hitting is that I always get this windows pop-up that says "File Download - Some files may be harmful..." Does anyone know how to disable this security feature?

[MHz]

This is what I use

RegWrite('HKCU\Software\Microsoft\Internet Explorer\Download', 'CheckExeSignatures', 'Reg_sz', 'no')
RegWrite('HKCU\Software\Microsoft\Internet Explorer\Download', 'RunInvalidSignatures', 'Reg_Dword', '0x00000001')
RegWrite('HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Attachments', 'SaveZoneInformation', 'Reg_Dword', '0x00000001')