It works!
As an earlier poster said you turn off plugin delay compensation in DP (setup>configure audio system >configure studio settings and uncheck Automatic plug in delay compensation)
Also you have to set the system to run all plugins in real time and turn off pregen in the preferences.
Then it works. You still get latency from the VSL EP system depending on the number of buffers. I'm getting 1200 samples with 2 buffers run on a macbook pro. But that's still a ton better than using external midi. Still working on the finer details of this but this is the first time I've got the thing up and running and I'm using 25 event input plugins, 250 midi tracks on a Macbook pro.