For cubemaps, you can use the nvassemble command-line tool. Yeah, it's a bit more hassle, but once you make a batch it's pretty quick to run the next time. I haven't used it, but I bet the images are in the same order as the old plugin... +X, -X, +Y, -Y, +Z, -Z, ... which translates to the 3ds Max directions RT, LF, UP,…