You can let MS Release inject a keyfile into packages before downloading. The keyfile will contain the current key of the logged-in user. When no-one is logged in, a keyfile will still be generated and injected, but it'll be empty.
|Inject Key||This will enable the Key Injecting system. Set it to no if you do not want to use key injection.||Yes|
|Key Filename||This will be the path and filename to the keyfile to inject in the zipfile. The path will be absolute to the root of the zip. You must enter a filename.||key.file|
Check your new settings by downloading a package from the front of your site. Check if it contains the keyfile and if it is in the right location.