cannot get all build configuration properties

Hi, 

I'm writing extension for Visual Studio. And in my extension I want to access the build configuration properties of current project.

I've been able to get the Properties of the build configuration via DTE using following code:

            SelectedItems selections = dte.SelectedItems;
            int n = selections.Count;
            SelectedItem s;
            if (n > 0) {
                s = selections.Item(1);
                if (s.Project != null)
                {
                    Configuration config = s.Project.ConfigurationManager.ActiveConfiguration;
                    props = config.Properties;

                }

But the "props" object has only a portion of all properties of the build config. It lacks one property that I'm sure is there. So how can I get full list of properties of the active configuration ?

Thanks !