VST: how to use third party VSTs and HALion together

In a project, I want some channels to use HALion sounds and others to use EWQL (Play). However, on the VST Rack, if I choose Play (EWQL), then HALion doesn’t appear on Track Inspector, and vice-versa. What should I do?

PS: steinberg.help doesn’t seem to be up to date with Dorico 4.

I do not find that to be the case (in Dorico Pro 4).
One can add VST’s in the VST tab of Play.

And one can then use the pull-down for each track to select the desired VST for the Player/Instrument
VSTlist

If one wants different voices to use different VST’s, checking Enable Independent Voices.

Here what appears for me: After choosing Play (EWQL) on VST Rack, HALion doesn’t appear as an option anymore on Track Inspector.

PlayHALion

That’s because you have replaced it with Play, rather than added Play as an extra VST. As @Derrek showed you, to add a VST click the ‘+’ button.

Ok got it, thanks.
Here’s a summary of the solution:

  • Play Mode → VST Rack → VST Instruments → DON’T change the HALion option → go to + and add Play