This is what I'm trying to do. First I had a XamDataGrid inside a ScrollViewer with scrollbar for the content disabled.

                <ScrollViewer x:Name="_scrollViewer" Grid.Column="0"
                              Width="{Binding Path=Content.Content.ScrollViewer.Width}" Height="{Binding Path=Content.Content.ScrollViewer.Height}"
                              HorizontalScrollBarVisibility="Hidden" VerticalScrollBarVisibility="Hidden">
                    <igDP:XamDataGrid x:Name="_grdContent" VerticalAlignment="Stretch" HorizontalAlignment="Stretch">
                        <igDP:XamDataGrid.Resources>
                            <Style TargetType="{x:Type igDP:RecordListControl}">
                                <Setter Property="Template">
                                    <Setter.Value>
                                        <ControlTemplate TargetType="{x:Type igDP:RecordListControl}">
                                            <ScrollViewer CanContentScroll="False" Focusable="False" HorizontalScrollBarVisibility="Disabled" VerticalScrollBarVisibility="Disabled">
                                                <ItemsPresenter/>
                                            </ScrollViewer>
                                        </ControlTemplate>
                                    </Setter.Value>
                                </Setter>
                            </Style>
                        </igDP:XamDataGrid.Resources>
                    </igDP:XamDataGrid>
                </ScrollViewer>
 

I then have 2 external scrollbars that control the content scrolling of the ScrollViewer.

                <ScrollBar x:Name="_horizontalscrollBar" Grid.Row="1" Grid.ColumnSpan="2" Orientation="Horizontal" SmallChange="100" LargeChange="100" Minimum="0" Maximum="{Binding ScrollableWidth, ElementName=_scrollViewer}" ViewportSize="{Binding ViewportWidth, ElementName=_scrollViewer}" Value="{Binding HorizontalOffset, ElementName=_scrollViewer, Mode=OneWay}"/>

                <ScrollBar x:Name="_verticalScrollBar" Grid.RowSpan="2" Grid.Column="2" Orientation="Vertical" SmallChange="100"  LargeChange="100" Minimum="0" Maximum="{Binding ScrollableHeight, ElementName=_scrollViewer}" ViewportSize="{Binding ViewportHeight, ElementName=_scrollViewer}" Value="{Binding VerticalOffset, ElementName=_scrollViewer, Mode=OneWay}"/>
 

This all work fine with some minor niggles:

1. The SmallChange & LargeChange property in the ScrollBar is not set. Thus clicking the RepeatButton & the arrow buttons of the scrollbar trigger a tiny amount of change. How I set this property properly?

2. Since I have a hierarchical grid, everytime I expand/collapse a record the height of the grid is changed, but the external scrollbar is not aware of this although it's bound to the correct properties (I think). So how do I 'correct' this settings?

Suggestions?