Libreoffice Jars - why not as maven dependency

When trying to build the plugins, my eclipse complains, that four jars are missing from /compilation-env/libreoffice3.6/.
In fact the whole directory is missing. I guess it must be created and filled manually before building.
But where do I get them?

And: Why not just use maven dependencies for these libraries instead?

Regards,
siiikooo0743