View port Center and size

Hi,

I need to get the view port at the center of the page with a specefic size

if followed one of the threads :
<ext:Viewport ID="Viewport1" runat="server" Layout="HBoxLayout">
<LayoutConfig>
<ext:HBoxLayoutConfig Pack="Center" Align="Stretch" />
</LayoutConfig>
<Items>
<ext:Container ID="cont1" runat="server" Width="1160">
// ext panel with accordion layout
//ext tab panel
</ext:Container>
</Items>
</ext:Viewport>

This solved the problem of centering, but the problem which followed was bigger ,

the North zone was fine , but west(accordion layout)was rendering at top of the page

pls help

Rajat