Cannot create classes in default package

Description of problem:
Data Modeler doesn't allow users to create new data objects in the default package. The package is not available in the list of existing packages and cannot be "created" through the Data Modeler as a New package either (via the choice between existing or new package when creating a new data object).
There is a package called <default>, that represents the Java default package, at the top of the list of packages in the Project Explorer. Users can easily create all other asset types in this package. Therefore, they should be allowed to use it for data objects/Java classes as well.

Version-Release number of selected component (if applicable):
BPMS 6.0 ER4