So I am trying to import 1099B transactions. 

there are about 400 transactions on the excel.

about 300 have wash sale disallowed. When i am importing the excel, it doesn't have a column for wash sale disallowed at the data mapping screen for headings

What do i do? do i have to manually input 300 wash sale transactions??

that doesn't sound reasonable, when it has the import function, but not able to import the information...