Vegas Pro effect masking?

I’ve got a particle effect that I’d like to have appear as though it’s coming from a foreground object. The fx is set up as “particle illusion” on the video track event, I’ve set up the tracking for the fx emitter and added a pixelchooser mask and set up tracking data for both. The particles are playing and tracking exactly were I want them.

I can’t seem to get the mask applied to the fx. Is there a tutorial I can go through or some non-obvious steps I need to get this working?

TIA!

Naturally I found these after I posted this.

https://borisfx.com/videos/particle-illusion-and-vegas-pro-effect-isolation-with-mocha-masking/

If there are more, please let me know.

https://borisfx.com/videos/continuum-blow-text-away-with-particle-illusion/

@PeterMcAuley I’d watched most of that (d**n impressive) but had the impression that it was somewhat AE specific. Was that wrong?