setup wizard silent argument

I have a solution that contains a setup project(made with VS2008 setup wizard). I need to have the option to silently install the setup project. I read that in order to do this, I should delete the User Interface screens. But this will make my setup project ONLY silent. I need it to be available to be used normally (non-silent), and when called with a specific argument, to be silent.

So my 2 questions:

• How can I pass arguments to the setup project?
• How can I create a silent install procedure, while also keeping the normal setup, when the project is called with no argument?

If there are resources on the web, please point me to them.

Setup exe can usually be run in silent mode using:

setup.exe /q

MSI can be run in silent mode using:

msiexec /qn /i setup.msi