Center nodes in a palette

I have load a palette with my node.

I don’t manage to center horizontally the different node. They are all align on the left.

i have set the palette layout like this :

<!-- Palette -->
                    <go:Palette x:Name="PaletteStepModel"
                                NodeTemplateDictionary="{StaticResource PaletteNodeTemplateDictionary}">
                            <golayout:GridLayout Sorting="Forward"
                                                 CellSize="75 5"
                                                 Spacing="5 5" />

In the Goxam 1.0 flowchart demo in Silverlight, with this exact same settings, the node are center in the palette. I would like to do the same thing.

I have tried to set HorizontalAlignement and HorizontalContentAlignement property on the palette xml node but nothing worked.

I’m obviously missing something. Can you help me please ?

I just tried this in Silverlight 1.0.1, and it worked just as one would expect when setting the Palette’s HorizontalContentAlignment and VerticalContentAlignment properties.

Nope - this does not work.

At best I can only get the entries in the palette to be all left justified.
Is there good documentation on maybe how to combine the "cellsize" and "spacing" settings when used with horizontalcontentaligment?
I am guessing these need to all work together but the docs are downright bad.
For example, CellSize="75 5" what is this top, left or height, width? What about Spacing? I read the docs and they desperately need examples.
What the heck does this mean in English anyway?
The default value is NaN x NaN. The units are in model coordinates. When the width is Double.NaN, the ActualCellSize uses the maximum of all node widths plus the Spacing width. When the height is Double.NaN, the ActualCellSize uses the maximum of all node heights, plus the Spacing height.

CellSize is a size, so the values are width and height.

Spacing values are width (horizontal) and height (vertical).