defining macro in weblog.vm

[Odelya YomTov-Glick]

Hi,
I am trying to define a new macro.
I defined in weblog.vm, sitting in the library: \WEB-INF\velocity of the
webapplication. 
#macro (showStringShort $string $size)
   $string.substring(0,$size)
#end

I call it from the template,like this:
#showStringShort("hello" 3)

But it displays:
#showStringShort("hello" 3)
As if the macro doesn't exist.
What did I miss?

Odelya