Qualtrics API - Signature Retreival

Context: 

I’m generating a React.js based form to provide a more aesthetic user experience/design, then pushing the results to Qualtrics via the Qualtrics API. The form requires e-signature for parent consent for a summer school program enrollment.

Issue:

I have been able to push all data through the API, except the <canvas> captured signature. 

The signature field is being sent, but it will show as the following:

The code being sent for the signature question is in the following format:

Payload: {
  "values": {
    // QID1 - 27 returns are working as intended
    "QID28": "data:image/png;base64,<canvas-image-string-here>" // Encoded Image String populates here
  }
}

Caveat:

I can’t find a specific area where it states if the Signature field is available to the Qualtrics API other than the Survey Sessions V2.

I’ve attempted the submission with the Qualtrics Form-field as a Signature Block, as well as an Essay Text Response, to which both fields showed no response for the QID in question.

My Request/Ask:

Has anyone been able to effectively return a e-Signature using the html <canvas> element to the Qualtrics API? If so, how?

I work for a smaller PK-12 School District and would like to find a free/cheap option to intake digital signatures for custom Web Forms and Applications. So advice on alternatives are also greatly appreciated.