> The -N option (custom defined build structure)
> allows one to specify the file type (using %t) in
> the file name that is saved to disk. This is the
> file *type* (e.g. .html) and not the file
> *extension* (e.g. .php). Is there any way to include
> the original file extension in the file name? 
You CAN NOT get php, cgi, sql, or any other server side code from the public
side of a web server. Only the HTML output and referenced files.
So the extension is correct, it's html not php.
IIRC, you add an assume php=text/html the extension is not changed.