In the symbolizer I am able to create a two layer symbol where I have a star
symbol inside a circle. the style options I use in the symbolizer are:

1) 
Symbol: "Circle"
Size: 20
Color fill: -1 -1 -1  (no color)
Color stroke: 0 255 0 (blue)

Symbol: "Star"
Size: 10
Color fill: 0 255 0 (blue)
Color stroke: -1 -1 -1  (no color)

  Result:
  i) Symbolizer Preview
     A big blue circle with white fill surrounding a single blue star eg. (  *  )

  ii) In the Map 
     A big solid blue circle eg. ((()))
  
 2)
Symbol: "Circle"
Size: 20
Color fill: -1 -1 -1  (no color)
Color stroke: *0 0 0 (black)*

Symbol: "Star"
Size: 10
Color fill: 0 255 0 (blue)
Color stroke: -1 -1 -1  (no color)

  Result:
  i) Symbolizer Preview
     A big *black* circle with white fill surrounding a single blue star eg. (  *  )
  ii) In the Map 
     A big *black* circle with a blue star in the middle. eg. (((*)))


Actual result: 
Since the file color of the circle is no color, the inside of the circle should
be transparent (i realize this may not be possible)

If it is not possible to have no color in a point symbol, than the interphase
should not have -1 -1 -1 in the Color fill and stroke. Black (0 0 0) would be
better to represent this issue for points, polygons can have no as a solid fill
color so -1 -1 -1 is valid for the interface.