We've created a step template for the deploy package step and we made the Package Id a Parameter. This works, until we assign a variable to this field e.g. #{MaintenancePackageId}, in which case the package id doesn't get expanded. The same seems to happen when using the variable directly in the step template without exposing it as a parameter.

The package #{Maintenance_package} could not be located in the built-in repository.

Plus, when using the step template and a parameter, the description of the step shows

"Deploy package #{ParameterPackageId}"

instead of the value being passed in. It does get executed directly when using a parameter and passing in a fixed field value.