Package Maker and postinstall ?

Hi,

I am playing around with the postinstall script of my installation
package.
The package is relocateable and when I let it install to the default
place,
it executes that script.

But not when I install it into /sw for sample.

Why doesn't it work in general ?

The content of the script simply collects some information and put it
into a file:

#!/bin/sh
echo $2 > /pwd.txt

Any ideas ?

I am using Mac OS X 10.3.9 and the XCode 1.5 tools.

Thanks, Lothar