Daily builds for PPA. Versions problem

[Anton Balashov]

Hello.
I'm trying to make automatic daily builds if there is new commits in git.
So, many commits have version 1.1.1 and I should to have many debs
with different orig.tar.gz
I want to have some like pkg-1.1.1-<date>ppa1
But when I'm trying to upload new version, I get an error:
pkg-1.1.1.orig.tar.gz was changes. And it's true.
I can put some part of commit hash in version (1.1.1~hash-date..) but
it's breaks order.
I can't have increment system here (or can but non-trivial).

How should I do that?
Thanks.