Survey Response Web Service Task Auth and Crypto How To

Qubie here (thanks! I have searched community and externally),

I have created a survey Action with the event source "Survey Response" with a Web Service Task; for a simple web service call this looks pretty straight forward.

Our need is to pass the survey response data from the Qualtrics cloud into our corporate intranet by calling a corporate web service. In the headers (no problem) we need to pass an HMAC Sha2 Http Digest (uh oh!). The service requires a call to get token, and then a call to pass the data (uh oh, two calls).

I will add that the Web Service Task has auth options (Auth is the first item on Web Service Request configuration, with options "None", "MySavedCredentials", or "Create New Auth" with type Token or Basic Auth. I do not see anything about this auth item or the options in the Web Service Task documentation. I do not think this supports my token/two call need.

1. How would I be able to use a crypto library to create digest of our secret and and a timestamp? Well, the only thing I can think of is using a javascript library in the survey, but it would not be very secure to have our secret in the javascript.
2. How would I be able to call to get token, then make call with the survey data?
3. Have I totally missed something obvious? Fingers crossed.