EWM - Create Posting Change with custom fields

Hi Guys

I have a requirement from a customer to create a Posting Change document with custom fields on both header and line item level in EWM using the below class and method:

- Class: /SCWM/CL_DLV_MANAGEMENT_PRD

- Method: CREATE_WHR

I have extended the Header and Items tables to include the custom fields through the EEW structures however these structures are not available on there are no EEW structures available on the importing parameters of method CREATE_WHR.

Has anyone worked on something similar and was able to overcome this challenge?