I have successfully set up continuous integration process using TeamCity for non-SalesForce projects, but need help with automating SalesFoce manage packages installation. To migrate metadata from source to target org, I used ant migration tool, but how to do in case of managed packages?
Questions:

1. How will TeamCity know that the new package has been created? I may watch the changes in source code tool, but not in the cloud where the created package is stored.
2. How to get the latest version of the package from the cloud? I need to compare the versions of the packages: the installed one and the new one
3. How to install the package using TeamCity?

Please help.