I\'m currently working on two projects simultaneously:
The solution I've used is the maven-ant tasks (http://maven.apache.org/ant-tasks/).
I added an install task onto the build.xml file, which installs the compiled .jar into the local repo.
While adding a full-fledged pom to the project would defintely be the best approach, this is a major chunk of work, and inflicts maven on the project (where the other users would prefer not to use it).