I know this is an old request, but this may help anyone searching tpl or smarty in hopes of accomplishing the same thing...
It took many tries, but this finally worked for me in smarty/tpl:
{php}include("/home/web1/xxxxxxxx.com/htdocs/tp/ssi_in.php");{/php}
You have to use the full directory path. On my server it looks like that and I replaced my domain with x's. Every type of server is different so you may have to ask your host for the full directory path.
I have a header.tpl file in my Adult Video Script and I put that code directly above </head> and it works correctly!
This replaces the first step in the TP manual that says to try either:
<!--#include virtual="/tp/ssi_in.php"-->or
<!--#include virtual="/tp/ssi_in.php"-->
I think you still want to do the step listed under warning where you are supposed to insert the following code right after start of <body>
<img src="/tp/img.php" width="0" height="0" style='display:none;border:none'>
I still did that to play it safe and nothing broke but I'm not certain its still needed ... no harm done, I don't think, it's just an invisible pixel.
