You should be able to do it by pasting the Sprite into the canvas then pasting a another sold Sprite that covers the paster object. The second object should have the destination out blend and just change the opacity to lower than 100. You'll also want to make the second object invisible when not pasting.
The only caveat is it never fades all the way to transparent, although it gets close.
No eta for a fix. I haven't touch the plug in a while.
The particles off screen aren't drawn so the only workaround I can think of is to move both the particles and paster object on screen before pasting.
Here's the offset.
Offsetx = particles.x-scrollx
Offsety = particles.y-scrolly
Subtract it from the partircle and paster positions,
Paste the particles,
Then add the offset again.