As I have mentioned in my earlier post, NetSuite Debugger is a great tool to find the undocumented details about the entities . Another way to find the list of fields related to an entity is through these functions.
Returns a normal keyed array of all the fields on a record. Note that the number of fields returned will differ when you call getAllFields() on the edit of a record vs. on the xedit of a record.
Returns an array of all the field names of a sublist on this record.