Popin for table populated with model context datasource node

Hi all,

I need a table with a row popin. I can see that several properties such as Table.selectedPopin must be bound to a String attribute under the table datasource node. Unfortunately the datasource node is a model node and no String attribute is available (they are all abap types such as amust, num4, ...). Moreover I cannot create String attributes there as the node is a model node and this operation is forbidden... how to workaround this?

Thanks

Vincenzo