Florent - I'm sending you this as an example of the way I would recommend supporting a maven build for this project. The way Adam has set up the packaging project is workable, too, but overly complicated for my tastes. The main difference I see is that he has set up a system of interdependent "pom" files in a so-called "multi-module" project. This has some advantages, since you can have one repository look like one maven project. However, Maven at its heart is about building a single artifact (like a jar, war, etc), so these multi-module projects are always a little difficult to work with. They don't automatically work in most IDEs for example. The way this one is set up is as two completely separate poms. There is of course a dependency between the two projects; to build this:

cd http-client-java
mvn install
cd ../http-client-saxon
mvn install

The "install" target installs an artifact in your local repository so it is available to be resolved as a dependency. Ultimately you will want to have them posted to "maven central" so they can be resolved over the internet, but that's a little more involved of a process that requires registering with oss.sonatype.org, giving them a PK cert, etc.