Multiproject and properties inheritance issue

I have some projects
common/all
common/model extends common/all
common/webapp extends common/model
party/model extends common/model
party/webapp extends common/webapp
doc extends common/all

Some properties are set in a project.properties file in common/all (for example maven.test.skip=true).

When calling multiproject from the "doc" subproject (which calls all projects), properties defined in "common/all" are not available to the party/model and party/webapp

If I define the properties in the "doc" project.properties everything seems ok.
If I run multiproject from common/all everything also seems ok.