Your comments

No progress yet. I'll let you know once there is something to test.

Can you please elaborate on your idea? You can already squash in the Journal. In which way will your proposal be different?

No progress yet. I'll let you know once there is something to test.

That's correct, the used library does not support custom definitions.

But you are requesting this feature for SmartGit's Git integration, not its Mercurial integration?