I'm not interested in the Soul Trap glitch.

I want to be able to cast Soul Trap on a Target, so I don't have to get close enough to touch while casting. You can do this in Oblivion, if I remember correctly.

I've tried to create the spell with 180 second duration and area of 5 feet. When I cast said spell, I get a little display of swirls around the target as if it worked, but the soul is never trapped.

Umbra Sword traps souls, as does Soul Trap (on touch), and Fphyggi's Gem Feeder--all those work fine.

Why isn't the Soul Trap on Target spell I'm trying to make working????

Are you killing the enemy while the spell is in effect? The spell itself is not enough, you have to also kill the enemy while it is in effect to capture the soul in the gem.

To that end, you have soul gems in your inventory? And, they are big enough to capture the soul you are trying to get?