Hello Yoro,
you don't need to integrate an OpenScape Button into CRM.
You call the OpenScape Client itself and to logon the same user as in the CRM aswell.
Therefore it's recommended to create a direct link which calls the Logon Screen of the OpenScape Client.
Please make shure that all neccessary Software components for the OpenScape Client are installed on the Workstation.
You also need to create a user in OpenScape with the same username as in crm.
Kind regards
Martin Gaschk