Cannot locate and map request header from webhook to HTTP Post Req

I have a catch webhook that receives a payload with some headers I have put in there. I am then taking that payload and looking to forward it over to a different endpoint with the same payload and those certain selected headers. I however cannot figure out how to map the specific headers I am looking for (USERNAME, PASSWORD, and ID) to the HTTP request’s headers section.

My webhook does have the header pickup setting enabled. It seems to only pick up pre-generated headers from Postman. Ive sent the exact same payload to an echo server + zapier and I can see those headers in there.