I tried with the built-in import/export functions in the struct schema editor (admin section). First exported/imported the schema, then exported/imported the raw data (as serial) into the new schema. At first, it did not work. Schema was transferred, data was not. There was a green message box, that said something like: "data successfully imported". But on the page the data was not shown in the struct serial editor. Until I realized that data pid in csv must match pageid of target page. That seems to be the part that needs to be modified to make it work, if you want to clone, split or transfer an existing dataset.