[ros-users] Stack depending on package

Hi,

when I add a package dependency in my stack.xml file, rosdep complains
about it not having the 'stack' attribute:

$ rosdep check orocos
[rosstack] bad depend syntax (no 'stack' attribute) in
[/home/steven/src/svn/robotics-ros/install/orocos/stack.xml]
[rosstack] invalid manifest
...

where the stack.xml file contains:
<depend package="eigen" />

Can a stack only depend on another stack and not on packages? I'm
working with boxturtle.

regards,

Steven