To answer my own question above: the trick was to use the

status

field and pass a

TransactionStatus

enum value:

_salesOrderPendingApproval

https://stackoverflow.com/questions/31197636/create-a-suitetalk-transaction-search-that-gets-all-sales-order-with-a-certain-s https://system.netsuite.com/help/helpcenter/en_US/srbrowser/Browser2016_2/schema/enum/transactionstatus.html?mode=package