Philipp, you previously had an arcticle about this PHP5 function, and that's when I started to use it.

But .. When loading an Amazon book page for instance, the table containing the price is mysteriously hidden. I found out they did this when no User-Agent is specified, to avoid being screen scraped.

So do you think it's possible to set a User-Agent in any way for this function?

Take a look at Curl for that:
http://de3.php.net/manual/en/ref.curl.php