Slinger does not execute cgi scripts or SSi commands

My slinger startup script looks like:

export HTTPD_ROOT_DIR=/cf/web/httpd
export HTTPD_ROOT_DOC=index.html
export HTTPD_SCRIPTALIAS=/cf/web/cgi
/cf/web/slinger -e -s -d &

the index.html page contains several SSI instructions like:

I use firefox to view the webpage. If I check the source received by Firefox, the html code still contains the instructions, so slinger seems just to pass them by instead of interpreting/executing them.

Any ideas?

Slinger supports a variety of SSIs (Server Side Includes) that can be
applied to an HTML document. This allows you to provide interactive
real time features that can be used to give your HTML documents dynamic
qualities without using CGI scripts or programs. Files which use
SSI should have a file extension of .SHT or .SHTM. Only the files
which have these suffix will be searched for SSI tokens.

“… a variety …”
such as ??
HELGE would like to know

An SSI is a special sequence of characters contained in your HTML page. As
the page is scanned by the server (slinger) before transmission, the
tokens are replaced by the server with dynamic HTML code. The format of the
SSI token is as follows:

<!--#<tag><arguments-->

Where

<!--# is the token prefix, all SSI tokens start with this.
<tag> is the SSI command to execute.
<arguments are the arguments that are passed to the commands.
           The arguments take the form argument="value".
-->   are the closing characters of the SSI token. 

The SSI supported SSI commands are:

echo    allows data from certain variables to be inserted in a HTML page
include allows the contents of a file to be inserted in a HTML page. 
exec    allows you to execute an external program and have any output
        data inserted into a HTML page.
config  allows you to set certain HTML output options.
email   can be used to have an email sent whenever an HTML page is accessed
        or an HTML form is submitted. An external email program will need
        to be specified. 
if      allows conditional execution of SSI operations and conditional 
        printing of HTML text based on logical comparisions
goto    allows you to jump to label token without printing skipped text or
		applying skipped tokens.
label   location to jump to with goto.
break   allows you to terminate a HTML document at any point. 
qnxvar  allows you to obtain data from a data server process.

thanks a lot.
guess I am going to buy some books tomorrow.
Helge