Issues with GTIN Exemption: Missing 'externally_assigned_product_identifier' and 'merchant_suggested_asin' Errors on Amazon Seller API

I have successfully acquired a GTIN exemption for a generic brand and the product type APPAREL_HEAD_NECK_COVERING. However, I'm encountering issues when posting data to my Amazon seller account via the REST API. Specifically, I receive the following errors:

1. 'externally_assigned_product_identifier' is required but not supplied.
2. 'merchant_suggested_asin' is required but not supplied.

Here's a summary of what I've done and the data I'm using:

GTIN Exemption: Successfully obtained for brand "Generic" and product type "APPAREL_HEAD_NECK_COVERING".
API Call: Using the REST API to post product data.

1. What should I include for externally_assigned_product_identifier? Given that I have a GTIN exemption, what value or format is required here?
2. How should I correctly populate merchant_suggested_asin? The schema requires this field, but I’m unsure how to provide it without a GTIN.

Any guidance or examples on how to format these fields correctly would be greatly appreciated!

Thank you in advance for your help