Probably something I have overlooked but is there a parameter that sets new registered Joomla-users automatically to registered K2 user?

Seems to me it's rather awkward to set new registered Joomla-users manually as a registered K2 user each time .

to have your new users as K2 users :
1) create a K2 user group and set the rights
2) Set the k2 parameter with this group (parameter > advanced > select default K2 user group)
3) use the k2 user module as login module, not the joomla login module.
If you use joomla login module, there is no k2 user created with the joomla user.

thanks, only problem is it is not possible to make a menu-link to a module.
Is there a way to get access to the K2-inlogmodule using a menu-link?

1)you can publish the k2 user module in an unused position of your template (ex: toto).
2)you create a K2 item with {loadposition toto} as only content.
3) publish a link of k2 item type, which target the item.

This is one way to do.