TAC case upload via SmartGrid API?

[USTUTT-KK]

Hi, I'm just looking at https://www.cisco.com/c/en/us/support/web/tac/tac-customer-file-uploads.html#retrieveuploadtoken and trying to understand where/how to get the Auth-Token. https://developer.cisco.com/docs/servicegrid/ doesn't really seem to give any clear answer or I'm just too blind to see it.. Is there maybe sample code using the SmartGrid and CXD in combination?

Thx, Kilian