There is a workaround.
Use LoopBe, the vitual MIDI driver.
It acts as a conduit of MIDI data from one application to another.
Install the driver.
From Encore’s MIDI setup, select LoopBe from the Port A and Port B dropdowns.
Then run your DAW of choice (e.g. Reaper or Ableton Live).
Make sure you’re getting MIDI from LoopBe.
Insert your VST/plugin of choice on a MIDI track.
In Encore, write your music on a corresponding MIDI track.
Press the play button.
Well, there it is.
Give it a try.