Obviously the kind of stuff I write is not exactly "harp" kinda stuff, unless you want to call the harmonica a harp.

But , to the point of the question. If there is a harp in a given synth, it would follow that you could simply load that sample and do a keyboard gliss and that should work just fine. Record it, capture it as a sample, whatever you wish.

That would be my approach should I find myself in desperate need of a harp gliss.

You can find my music at:
www.herbhartley.com
Add nothing that adds nothing to the music.
You can make excuses or you can make progress but not both.

The magic you are looking for is in the work you are avoiding.