Server Side includes in V4R5M0 Original Server

I have a customer where we just updated with HTML pages that have server
side includes.  The included files aren't processed as part of the page.  A
little research indicated that I needed to add an "AddType" using the
following syntax:

AddType .shtml text/x-ssi-html 8bit 1.0

I stopped and restarted the server but the page still doesn't display the
included files.

Here is the HTML:

<!--#include file="header.html" -->

  <TABLE WIDTH=750 BORDER=0 align="center" CELLPADDING=0 CELLSPACING=0>
          <TR>
                  <TD width="750" valign="bottom"><img src="images/mainBody.jpg"
width="750" height="316"></TD>
          </TR>
</TABLE>
<!--#include file="footer.html" -->

Header and footer nevers displays.

What did I miss.

Thanks,

Pete Helgren