I just tried it... and it didn't work.
I downloaded and installed the latest Hijack (245) and Jemplode bleeding-edge JAR file (29).
Then I opened a copy of my original animation that had been posted to this BBS last week. I opened that animation in the Jemplode animation editor. It played back correctly. Tux waved at me, all seemed well inside the animation editor.
I selected "upload animation" from the menu in the Jemplode animation editor. The computer made a short beep. Then, after a pause, Jemplode reported "upload complete".
I rebooted the empeg, and it was still the Hijack-penguin animation, not the one I'd attempted to upload.
Did I do something wrong?