When using Oauth 2.0 Authentication, I recommend using the TruClient protocol.
If this does not work in the TruClient Protocol, the only other option is to create a web service script. The Web (HTML/HTTP) protocol does not support Oauth/SAML 2.0 Authentication.
* Add the correct custom web_add_auto_header function to the script
* Depending on the size of the OAuth2 Token response, you will need to add the web_set_max_html_param_len(); function. You can verify with your developer on what this function limit max needs to be set at.
* You will need to identify the OAuth2 Token from the capture , and manually capture the value of the OAuth2 Token authenticate for every request through the rest of the script. This is created behind the scenes and not scene by http capture. Manual correlation of the OAuth2 Token, placed above the correct URL within the script, will be required, or the OAth2 Token will never be seen.
* A final token maybe needed, to be captured to be used to keep the logon connection alive. You will need to work with your developers and reviewing of the application capture from Fiddler or HAR, to find out.
I hope this helps