I'm deploying .NET Framework 2.0, wich requires Windows Installer 3.1,
so I need to determine what Windows Installer version is installed on
each machine.

The only way I've found to determine it is looking the version of the
file msiexec.exe.

Then, I want to check it in a distribution rule of the app, but I need a
method to accurate the distribution.

Can I use a macro (*WinSysDir in this case) in the distribution rule?