Can you add the notation elements of OPC Unified Architecture (OPC UA) to yEd?
This is especially the base shape:
_______ / / \______\
The arrow shape:
<|<|---- (filled and not filled)
And maybe a smaller version of:
-||----
You can find an overview of the notation (only the 'simple notation' is required) here:
http://www.commsvr.com/UAModelDesigner/html/4ff5fa83-9b3b-4c4f-8160-f5261ba30633.htm