Comment 3 for bug 1116560

Ah, so sorry that this isn't documented properly. One of the things about buildout is that it separates the packages that are available -- which is what lava-develop-local manipulates -- and which packages are *used* -- this is specified by the value of the 'eggs' entry in the [server] section of the buildout config (plus the dependencies of those packages). So to install a custom extension, you need a custom buildout.cfg, somewhat like what is explained here: http://lava-deployment-tool.readthedocs.org/en/latest/#limited-deployments (except with += rather than -=)