Trial 11 a.k.a How to do Sonic boom right after neutral punch.

Pretty much the title, but basically in Trial 11, its Jump H Kick > Stand H Punch > Sonic Boom.

Now you can't be pushing back, or it doesn't count, so I can't keep charging after the punch to keep the combo going. Am I doing something wrong? I've tried looking for something to tell me kind of how to do it, but I can't seem to find something. (With the exception of this clipclip, which is good, but I wish I could slow it down.)

Maybe someone could explain it to me?

Thanks