Lukasz -
The sequence in the sequence file that you reference is the implementation for the "Import/Export Properties..." item in the Tools menu. It expects information to be defined in the context that only exists when a top level sequence. It is also a dialog not a programatic interface.
NI does not have any shipping step type to do programatic exporting of property information, just importing. The only low-level recommended option available is PropertyObject.GetXML().
Scott Richardson (NI)
Scott Richardson
https://testeract.com