The 3DE aren't able to run on the regular Arma2 Version and i'm afraid that nothing would change that in the next months.

But the MAP_EU for ArmA2 is linked to the original BIS Model pathes, so they are placeable in the Editor or Ingame.

Of cause the AI needs Island placed Roads to use them correctly, but for any kind of Editor solution the EU can be used, the model pathes are 100% BIS.
So after a Visitor Import of the produced data all pathes work in the exact way like the road objects have been placed via Visitor.

(The mission shadow projection on editor placed Roads belong to some priority changes in the RVMATs, after island implant they are OK !)

For ArmA1 with a better useability with the 3DE we have made "our own" centered roads based on the BIS roads because they are much more handy to place them with the 3DE.

If you need anything help with addons or configs feel free to pn me, i have also a need on tools for better island editing, Visitor is imho unhandy for effective work.