Newbie Question-Constant sound from a software instrument?

I'm using the Nature Sounds instrument from the library for rain. But with my midi, the rain will only play for like 10 seconds before it stops. So I looped that but you can hear the fade out and in and it sounds pretty bad. I know I could just go find a longer mp3 of a rainstorm and use that but I really like how this one goes with what I'm making lol, so any help is appreciated. Sorry I'm not very Logic-eloquent, hope this makes sense. Also I'm using Logic Pro X.