Open New Tab control in MVVM

Hi,

I am working on a new WPF application in MVVM pattern.  I am using Josh Smith's for all my interactivity with RelayCommand.

I can add as many commands/buttons as I would like on a MainWindow.xaml view.  Each command would open a tab control in a main workspace. But I am looking for a way to open a new tab control from one of the views (which is not the MainWindow view).