Though just
project: 'Pier' copyFrom: 'Seaside' with: [
spec
className: 'ConfigurationOfPier2';
loads: #('Core');
file: 'ConfigurationOfPier2';
repository: 'http://smalltalkhub.com/mc/Pier/Pier2/main' ];
ought to be enough. Your copyFrom: only sets the version.
Stephan