How to Customize the Left Navigation Bar of SPPS Home Page [Another Solution]

There are a few steps to achieving this:

1. Identify the Category ID for your "Departments" area.
2. Modify the underlying .ASPX file
3. Add a NEW instance of the control that renders this heirarchy
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1. To get the "Departments" category ID
- Open the "Deaprtments" area in your browser
- Click on the "Change Settings" link
- Look in the URL for the following:
    CatID=9d576751-eeea-4392-8381-9a4ad043056f
- The number (which will be unique to your Department area) is what we want
for the next step.

2. To add the correct navigation control
- Open the following file:
    C:\Program Files\Common Files\Microsoft Shared\web server
extensions\60\TEMPLATE\1033\SPS\default.aspx
This is the underlying template for the SPS Homepage

3. Add a NEW instance of the control
- Look for the following:
  <SPSWC:CategoryNavigationWebPart runat="server" id="VerticalNavBar"
DisplayStyle="VerticalOneLayer" />
- Replace it with the following
  <SPSWC:CategoryNavigationWebPart runat="server" id="NewVerticalNavBar"
DisplayStyle="VerticalOneLayer" CurrentCategoryID="<insert from above>"/>
- Note that I have given it a new ID, you MUST do this for it to work.

In the default.aspx page (http://server/default.aspx) you
also need to replace the CategoryNavigationWebPart with
the new instance: 

<SPSWC:CategoryNavigationWebPart runat="server" 
id="NewVerticalNavBar" DisplayStyle="VerticalOneLayer" 
CurrentCategoryID="<insert from above>"/>