Where is the cancel button on the empeg (non-rio) remote?

You have an actual Empeg remote? Those are very rare. But if you do, it should be labeled exactly as the Rio remote and "mark" should be clearly indicated.

If you mean the Kenwood remote, the cancel key is the asterisk, but it won't mark the track. If you have only a Kenwood remote, then the 4 key has to mark the track, and if Hijack blocks that feature on the Kenwood remote, then we need to look at the possibility of altering that feature on Hijack somehow so that it doesn't leave Kenwoood users out in the cold.

Button guide is here, please refer to it for button documentation.