Thanks, I took a look at the php file and method you suggested, I'm afraid it's my turn to not be sure I understand :-)
I see a bunch of bits which look interesting in there (e.g. $this->request->get['customer_id']), but the problem is I don't know how my php code can instanciate the "$this". I am too much of a beginner with respect to MVC frameworks, so I am hoping to simply be able to "get the cookie / read it", perhaps using some premade AbanteCart functions, in order to know who is logged in.
This code would be on the same domain, at the root, so there would not be any cross-domain issues for retrieving the session information, if that was your question? So basically this is external code, but (I think) it still resides "inside" the session...
Hope this is more clear! Tepp