Hello Uldis,
Composition associations are just a pointer from a parent node to a child node and vice versa (ref. documentation SDK1405 p.679). So accessing the data in the nodes should not be problematic.
Perhaps with more information on your context's issue, somebody could help you.
In which Business Object are you? A Custom one or a standard BO?
What is the screen you are in for this Data List?
Thanks,
Regards,
Jacques-Antoine