Right now it is implemented in our internal base class by calling the Activator.CreateInstance for the default constructor.
Do you need to create the object in a different way or would that be enough?

In Caliburn the parameter class implements it like this

    protected override Freezable CreateInstanceCore()
    {
        return new Parameter();
    }

The parameter class is used in this way:

<UserControl x:Class="Caliburn.Micro.HelloParameters.ShellView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:i="http://schemas.microsoft.com/xaml/behaviors"
xmlns:cal="http://www.caliburnproject.org">
<StackPanel>
<TextBox x:Name="Name" />
<Button Content="Click Me">
<i:Interaction.Triggers>
<i:EventTrigger EventName="Click">
<cal:ActionMessage MethodName="SayHello">
<cal:Parameter Value="{Binding ElementName=Name, Path=Text}" />
</cal:ActionMessage>
</i:EventTrigger>
</i:Interaction.Triggers>
</Button>
</StackPanel>
</UserControl>

as well as generated in code by Caliburn's conventions.
It seems to work fine in Caliburn.Noesis without me implementing CreateInstanceCore, I'm just not sure what it does internally in Noesis and whether it basically achieves the same thing without me having to override it?
If the same thing is achieved, then for MY purposes this can be closed. However there might be SOME types that want to customize how the instance is created, so it would be nice to be able to override it I guess (personally never had the need, I always just called the default constructor when overriding this, but it CAN be a use-case, to want to call a specific constructor to create the C# instance)