From my point of view at the moment git-buildpackage is only intended for using upstream sources which are not in the same repository. I already have a git-buildpackage repository with the branches "master", "upstream and a tags from the initial import via git-import-orig.
I cant find a howto, to have a development branch in the repository and import the changes from there into the upstream branch and make it buildable by git-buildpackage. I think the answer lies behind the steps git-import-orig does with the repository, which i dont know yet.
Any suggestions about having one repository which is git-buildpacke compliant and can be used to