If you are using Import, you cannot reflect the Bonus in the Bonus Pay Record ID as this import is designed to reflect only in the Record type Other Pay.
If you wish to display this in Bonus Pay, then you should only use the method below. However, this method will require you to either enter the bonus amount manually in the Bonus Pay Record or set the parameter in the Bonus wizard.
Go to Pay Record and click New.
Select Record Type as Bonus Pay and click Next.
Set the Bonus Report ID, Bonus Payment Period, Factor, Bonus Wage, and Prorate Factor.
Click Save and click Next.