I want to publish a beta version of some app of mine on the android market and face the problem that I cannot upload an app with the same packa
We upload but do not publish beta versions of our apps. Once uploaded, the market will assume that any incoming license check is being done from a legitimate installation that was side loaded and will respond "licensed". So our beta testers can test a full implementation, including the licensing code. (Test account responses are also honored for uploaded but unpublished apps.)
When the testing is complete, we upload the release version using the same package (and signing cert), and publish.