Last week one of my colleagues had trouble copying queries between two CompositeProviders using RSZC. Searching accross the internet and SCN ended up in people stating to have the same problem. It seems that still a lot of people are unaware of the fact that the technical name of an CompositeProvider is different than the technical names of any other InfoProvider.
When creating a CompositeProvider the system automatically adds a additional prefix of @3 to the InfoProvider name as mentioned in the SAP Help. So in case of a CompositeProvider with the name CP_0003 the real technical name is @3CP_0003. Using this complete technical name it is possible to copy queries between CompositeProviders using transaction code RSZC.