Installshield Setup.iss szdir=variable

[Kandissa]

Using Installshield silent install setup.exe -r a setup.iss file is created.

It has a line that reads szdir=C:\Program Files\Prog_Name

where the program files are installed.

I wish to know if there is a way to use Windows Environment Variables,eg.

%PROGRAMFILES% as szdir value so that the program may be installed in

computers with different system drive letters eg.

E:\Program Files\Prog_Name

N:\Program Files\Prog_Name

Thanks to all who bother to answer.