Set Point At A Location

[Uri H]

Hi There,

I'm using PHP MapScript with MapServer v4.3 (details below), and I am trying
to set a symbol at a specific coordinate, but instead of setting the symbol
on the coordinate, it appears at the designated image pixel offset.

For example - I have a world map, and I'm trying to set a symbol on London
(LAT=53 30' LONG=0 07'),

My code looks like the following:

$pointx = 53.5;
$pointy = 0.1167;

$point = ms_newPointObj();
$point->setXY($pointx,$pointy);
(and then attaching it to a line -> shape -> layer..)

The problem is that the point doesn't appear in London, but on the image at
the pixel location if [0,53].

How can I set the point on a specific lat/long?

Thanks Ahead!
- HU