HTTP Authentication

I'm looking at the requirements and testing out different SMS functionality for One Time Passwords. I am still unable to determine exactly how to place in CURL requests that vendors provide as examples while utilizing HTTP authentication.

Vendor Example:

curl -X POST http://api.twilio.com/2010-04-01/Accounts/ACXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX/Messages.json \
--data-urlencode "From=+15017122661" \
--data-urlencode "Body=Body" \
--data-urlencode "To=+15017122661" \
-u ACXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX:your_auth_token

The F5 Code I am attempting to use for HTTP Authentication

Form Parameter For User Name ACXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Form Parameter For Password your_auth_token

Form Action api.twilio.com/2010-04-01/Accounts/ACXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX/Messages.json

Hidden Form Parameters/Values
from +15017122661
body body
to +15017122661

I have attempted multiple iterations, the -u is a requirement as it passes username/token, but I can't find any other way to pass those values in the form field. How would the hidden form Parameters/Values field take a -u value for formatting purposes?

 Form Action api.twilio.com/2010-04-01/Accounts/ACXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX/Messages.json
 Hidden Form Parameters/Values
  from +15017122661
  body body
  to +15017122661
  -u ACXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX:your_auth_token