This is an inflammatory post,
In current version of Twitter provider the SendMessage API only have text as Input Parameter. By running this service, once can get error from twitter as screen_name, user_id or id is required.
To fix go to <>/packages\WmTwitterProvider\connectors\com.softwareag.cloudstreams.twitter_v1.1 folder and edit com.softwareag.cloudstreams.twitter_v1.1.xml file. Now find resource entry for path /direct_messages/new.json and modify parameter with name "screen_name" and make isRequired property as "true".
Now save it and reload the package. Refresh your designer and recreate the connector. You will see an input called screen_name now.