xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:MyControl="clr-namespace:MyControl"
xmlns:UpgradeUI="clr-namespace:UpgradeUI" xmlns:GameUI="clr-namespace:GameUI"
mc:Ignorable="d"
Height="100"
Width="300"
x:Name="ButtonScrollArea"
>
    <Grid x:Name="Buttons" />
</ScrollViewer>

using UnityEngine;
using System.Collections;
using Noesis;
using UnityEditor;

public class TestNoe : MonoBehaviour
{
    void Awake()
    {
        var gui = GetComponent<NoesisGUIPanel>();
        var root = gui.GetRoot<FrameworkElement>();

        Grid g = root.FindName<Grid>("Buttons");

        for (int i = 0; i < 10; i++)
        {
            Noesis.Button b = new Noesis.Button();
            b.SetContent("TEST");
            b.SetHeight(30);
            b.SetWidth(100);
            b.SetVerticalAlignment(VerticalAlignment.Top);
            b.SetMargin(new Thickness(0, i * 30, 0, 0));
            g.GetChildren().Add(b);
        }
    }
}