Jpeg2000, fnordware alpha bug?

I noticed that Max supports Jpeg2000 and I was consdering using it, but I've run into a problem.

When I compress my sprites which have alpha channels using the fnordware plugin for photoshop at 50% compression, and then reload them into photoshop, parts of the sprite which should not be transparent, like the middle of a character, are now slightly transparent.

Has anyone else run into this issue? If I use the lossless mode, I don't see the issue, but then my files are compressed no more than PNG. And if I use 90% then the issue is less noticeable but still there.

JPEG is not officially supported, only through an AXE module (skids modserver)

But yes, I ran over this problem as well. But I'm not surprised, its the same issue as with JPG: If you want to have transparency etc correctly, you have to use loseless as such informations are broken otherwise.

I would wager though that it is possible to encode the alpha channel in a JP2 image differently from the color channel, so you should be able to, with the right JP2 compressor, reduce the color depth of the alpha channel to 8 color or something and encode that losslessly, or much less lossy, while encoding the color channel as lossily as you want.

I guess it is not possible to do this with fnords' though. Has anyone else found an app they can do this sort of thing with?