So....
I finnaly got it !!!

Here is the screen :




Here is the code :

<!-- TEST ZONE START -->


		<moi:PaletteHeader id="MyHeader" activeTab="MyTab" ontabchange="HandleTabChange( this );">
			<table>
                  <tr> 
                        <td><moi:TabButton id="MyTab" class="SingleTabButton">
                            <moi:Text textid="Draw solid tab"/></moi:TabButton></td>
                  </tr>
			</table>
		</moi:PaletteHeader>
        
		<moi:PaletteBody id="MyBody" >        
    		<table id="MyTabContent">
                  <tr>
                    	<td><moi:CommandButton style="icon:icons/PlaneSetIcon.png;" commandSet="planes">
                        	<moi:Text textid="Plane"/></moi:CommandButton></td>
                    	<td><moi:CommandButton style="icon:icons/BoxSetIcon.png;" commandSet="boxes">
                        	<moi:Text textid="Box"/></moi:CommandButton></td>
                     	<td><moi:CommandButton style="icon:icons/SphereIcon.png;" command="sphere">
                            <moi:Text textid="Sphere"/></moi:CommandButton></td>
						<td><moi:CommandButton style="icon:icons/CylinderIcon.png;" command="cylinder">
                        	<moi:Text textid="Cylinder"/></moi:CommandButton></td>
                   </tr>
                   <tr>
                       <td><moi:CommandButton style="icon:icons/ConeIcon.png;" command="cone">
							<moi:Text textid="Cone"/></moi:CommandButton></td>
                       <td><moi:CommandButton style="icon:icons/TextIcon.png;" command="text">
                       		<moi:Text textid="Text"/></moi:CommandButton></td>
                       <td><moi:Text text="Cylinder"/></td>
                       <td>text</td>
                  </tr>
                </table>
		</moi:PaletteBody>
        
        
<!-- TEST ZONE END-->

One thing important I discovered while correcting some bugs : the ID of the table (wich contains icons and commands) must be exactly named like this :
[ID_of_tab-in_header]+"Content"

ex:

....
<moi:TabButton id="MyTab".....>
.....
<table id="MyTabContent">
.....
</table>

Is it right Michael?

+++