There should be an setLdifDirectory(File dir) method you can use on the ApacheDS instance to give it the path to the LDIF file. You can set this and the server should load the LDIF for you. You can either select an individual LDIF file itself and provide that as the argument or you can provide the file of the directory which contains a set of LDIFs that need to be loaded.
I have apacheDS 1.5.2 running under jboss with the attached MBean implementations.
I am trying to use H.350 extensions and I had it working with 1.5.1 (other DSService.java) but the vast changes between 1.5.1 and 1.5.2 have left me stuck. I did not see any unit tests that test loading of extended schema's from ldif files which is how I got my partition working again. If anyone can point me in the right direction, I would appreciate it.