How to set brand/business unit on Deal record through integration

Hi! We are creating Deal records through a custom-written integration. When the Deal records are created, we need to set the brand (business unit) property.  The integration checks to see if the value being passed in exists in the options listed for brands. We have confirmed that the values we are sending in match the internal IDs shown in HubSpot for the different brands, yet we keep seeing the error that the values sent in do not match anything in HubSpot. It does work when we hard code in a value.  I did find the topic linked below post that describes a  similar issue. Does anyone have any additional information on this problem?   https://community.hubspot.com/t5/APIs-Integrations/Use-Business-Units-with-API/m-p/551850#M49944