The ojp/JKE team is working on getting the SP levels to work in MP. That means that it will be possible to fight the JA enemies using ojp/JKE fighting mechanics.
And we keep procrastinating that we'll release v1.3 soon. Hmm. One of our mappers (jack) has been doing most of the work on getting the SP maps fully compatible with MP (through 'entity hacking')
Our forums are here if you wanna keep updated.