[mapserver-users] hollow line symbol

[Markus Spring]

I know it has been asked already, but checking the given answers I was
not successfull :-(

So my question is:

How do I create a hollow line symbol, especially one which can be used
together with a dotted line for a railway symbol?

(For a railway I could "white-print" the spaces, I know, but for a
true ========== line style?)

Markus