Hi,
You are right. In order to follow the approach I mentioned above you will need to implement theINavigationAware interface in the view model of the correspondingSubsystemDetailsView. This will allow for the view model to "participate" in the navigation progress and receive the parameters passed in the navigation request.
You can find more information about this in the following section of the documentation:
Regarding the IConfirmNavigationRequest interface, I believe it's not required to implement it for this particular approach. This interface is used when you want to give a view model the ability to confirm or cancel a navigation request (for example, if there are unsaved changes in a view) when the view is "navigated from." The use of this interface will depend mostly if you need to take advantage of those capabilities or not.
You can find more information about the IConfirmNavigationRequest in the following section:
Regards,
Damian Cherubini
http://blogs.southworks.net/dcherubini