Rather than spend an eternity making new crates in EP and adding tracks manually, I have found a method of transferring the “crates” from VDJ to EP.
In VDJ, click on the filter or virtual folder you want, so that the tracks appear in the main VDJ browser window. Highlight all of them (or some) and drag them across to the sidelist area. From there you can save to M3U. Unfortunately you can’t export straight to M3U - you have to do it from the sidelist area.
Then import the M3U files into iTunes. At this point you can access them from EP. In EP you can create a new crate or playlist by right clicking on the listed iTunes playlist/crate.
Now I have all my VDJ “crates” on the Prime 4. Yay!