We import custom datatypes and nodetypes into SDC by scripts. Custom nodetypes and datatypes are correctly showed in the SDC GUI. A new custom service is created based on such nodetypes by GUI. Steps are described into details at

https://lists.onap.org/g/onap-discuss/message/16068

A csar file (see attachment) is created by SDC that does NOT contain the custom datatypes.

JTosca validation fails due to the lack of custom datatypes inside csar file that therefore seems malformed. 

PS:

SDC catalog datatypes we retrieved by  https://XX.XX.XX.XX:30204/sdc2/rest/v1/catalog/dataTypes/ are shown in the attached file  "get_SDC_catalog_datatypes.json"