Login to eSignLive via my software

Hello, I'll try to explain my problem as clearly as possible. I work in a company who develop a software in 4D (programming langage) We sell this software to different client and we would like to integrate eSignLive in our software (that means that the client generate documents in the software and want to sent it to be signed, directly from our software). The basic functions are working (creating a package, adding files, roles, etc..) thanks to the REST API and the API Key found in my sandbox account. My question is, is it possible to allow our client to login to their eSignLive account with their mail and password directly from our software (using oAuth2 for example ?) retrieve their API Key or access token and do the operation with their account ? How is it possible ? I saw the documentations for the SDK's single sign on (http://docs.esignlive.com/content/c_integrator_s_guide/sdk/j_session_authentication/authenticating_single_sign-on.htm), but I can't make it work. What is the PROVIDER_ID for ? and the endpoint in the link below ? https://apps.eSignLive.com/oauth2/login/{PROVIDER_ID}?endpoint=http://apps.eSignLive.com/connectors/designer/{PROVIDER_ID}?{PROVIDER_SPECIFIC_PARAMS} Hope my question is clear and that someone can help me! Thanks in advance Thomas