Draw a connector on a blank page
Open the document stencil, there will be a standard connector master.
Open the connector master by a double click
Select the connector, go to "groups" in the menu and choose "transform into group"
Having the connector selected, open the context menu (right mouse click) and choose "open group"
Insert 2 boxes and format as needed
close the group, then the master.
Now when you draw a new connector, the standard connector with its two boxes will be used as master.