How to pass sfx settings to the SevenZipSfx class

Question

Does anyone know how to pass the sfx settings for the SevenZipSfx class located at http://sevenzipsharp.codeplex.com/. I need to specify what file to run, etc. I just took one of the samples e.g

;!@Install@!UTF-8!
RunProgram="setup.exe /s"
GUIMode="2"
;!@InstallEnd@!

and set it via the sfx.ModuleFileName property but its fails with null exception when I call the sfx.MakeSfx(@"C:\a.7z", @"C:\test.exe"); inside the GetSettingsStream(...) as the settings.key is null

I don't think this is the correct way but can't seem to locate where its reading the settings from. I don't want to hard code this in the source.