Extending theme and accessing resources.

I created a project with a theme and some resources (icons images etc.)
Now I need to create a new project, extending the previous one with its own theme (in order to add some resources).
I created a pom dependency form the previous one and created the new theme in the proper directory but when I try to reach resources of the first project (like icons) I get a null.
What I missed ?
Tks
Tullio