Avalon Dock 2 Open Dialog-Window as Floating Pane via Caliburn

Avalon Dock 2 Open Dialog-Window as Floating Pane via Caliburn

I have WindowView and a WindowViewModel, where WindowView is simply
derived from Window.
I open this Non-Model dialog via Caliburn's Window Manager; i.e.
_windowManager.ShowWindow(_windowView);
How can I make 'WindowView' a floating pane that can be used by Avalon
Dock [Version 2] ?
I've thought about deriving the window from
LayoutAnchorableFloatingWindowControl but its constructer is internal, and
I'm not sure how to implement LayoutFloatingWindowControl (which is
protected ctor).
A nudge in the right direction would be much appreciated. :)