Hi:
If you are using the BI Platform or the SAS Platform for Business Analytics, you can create packages from a stored process and the EG Stored Process Wizard allows you to select packages as the result type in one of the steps in the process. When you are using Management Console, you can specify package results for a manually registered stored process however, Mgt. Console also uses packages to "pack up" some of the metadata information for moving to other repositories.
Once you have registered you SP to return packages (whether in SMC or in EG), the spk file will be returned to the requesting client as a result of running the stored process.
cynthia