NetSuite - SuiteScript populate WBS Project structure

Question

I need populate WBS structure from project.

WBS table has one sublist lines. Lines has serializedamounts field but I cant populate this whith Suitescript.

serializedamounts = {string} [{"key":827,"lineKey":45,"type":"Cost","eac":4456,"date":"2021-01-01"},...]

Table -- Sublist -- Item in Sublist WBS --> lines -- serializedamounts 1 -- 1-teste -- {"key":827,"lineKey":45,"type":"Cost","eac":4456,"date":"2021-01-01"}