How to consume a SOAP Webservice from SharePoint 2013 using OAuth on premise

Hi,

we try to consume a custom webservice that we created which is hosted in SharePoint 2013 on premise. As pure windows authentication is dedicated in SharePoint 2013 it seems that OAuth is the authentication method of choice.

Unfortunately we always end up in 401 - unauthorized.

Are there any tutorials or best practices of how to consume webservices from SharePoint 2013 within K2?

thanks

Sven