Select Edit, Master Files, Inline Accessories and add Rotaball Connector as row D with image 5588 as shown below.
As with all inline accessories, the description shown in the master files is to help you choose the image that is to represent the item. You can describe the item in any way you like.
When you are drawing the Rotaball, press the spacebar to reverse the direction of the connector as needed. You can also come back later and switch the direction if needed. To do that, press F11 to get into select mode, click the tag of the rotaball and press the spacebar to switch the image.
Rotaball image from fogt.com