GPO and .MST file

I make a ccleaner.msi to use with GPO .

I use "Veritas discover" in the CD of Windows 2000 Server to create .MSI.

The GPO works but i need to activate :

" Clean at startup of PC" on all my 500 PC.

To do this by GPO , il need to create an .MST file

My question

How i create this MST File to use with my GPO ?