Nested trees design in Bazaar

I'm after this[1] article. I would like to know how i can create a similiar structure to this[2] one. Precisely specifing my problem, i want to nest module1/trunk and module2/trunk as subbranches in master branch project1. Visualizing this:

repository/        # Overall repository
 +- project1/      # master branch
 |   +- module1/
 |       +- trunk/ # branch
 |   +- module2/
 |       +- trunk/ # branch
 |     ...

And another goal i want to achieve is convenient checkouts. Something like:

bzr co bzr+.../repository/project1

- entire project with modules,

bzr co bzr+.../repository/project1/module1/trunk

- on开发者_运维知识库ly this branch.

I tried to use bzr split/join --reference, but master branch checkout didn't pull any modules (subbranches).

[1] http://wiki.bazaar.canonical.com/NestedTreesDesign

[2] http://wiki.bazaar.canonical.com/SharedRepositoryLayouts#project-trunk

Use bzr-externals plugin to achieve that.