"Endless" premade terrain?

I’ve looked through the documentation and the terrain forum, and it seems like you can only do infinite terrain either procedurally or with image heightmaps.

Is there any way to make j3o terrain with JME’s terrain editor, then have it loaded with terraingrid the same way it can load heightmaps?

If not, is there any way to extract or convert the terrain j3os to height/alpha maps?

You can do it with j3o’s, theres even an example. But the TerrainGrid is deprecated and theres nothing to replace it yet.