Dear pritam, thank you again for trying to help. Unfortunately, as I already mentioned above, the index.php file of the template where one is usually supposed to put the code (and as shown in the tutorial you linked to), does not have the necessary tags to put the code in in JA_Limes. Supposedly it works differently with the T3 framework.
In one Forum thread I read that one has to use a custom html module, but the participants could not agree on the correct position for this module. Now at least I know that the usual way via index file doesn’t work with this template, I hope I can find the solution now that I know what I am looking for.