Xlabs 2.0 - Master-detail navigation

I'm starting using Xlabs, and am struggling with how to go from master to detail, passing the object to edit/view.

NavigationService.NavigateTo(parameter,animated) seems to be the right candidate - but when I use it as follows:

NavigationService.NavigateTo<VenueDetailsViewModel>(MyVenue);

The no-argument constructor for the VenueDetailsViewModel is called - without the MyVenue object.

Should I be using Navigation.PushAsync instead?

Can someone point me to a worked example and/or documentation?

Edit
Forgot to say I'm using ViewFactory to register my pages and ViewModels.

Thanks,

James