6/9/2011 12:51:18 AM
When you go to the website of the Braille Authority of North America (BANA), and look down the left margin, click on the link for Latest Code Updates. There is an update there for Nemeth Special Symbols Clarifications, which may be what you were referring to in your question.
The calculator key (edk) and calculator window (edw) symbols, could be considered unlisted signs of shape (see Rule XVI section 107.), even though they have become commonly accepted amongst transcribers. As such, and since they occur only once in the text, I would list them in a transcriber's note at the point in the text prior to where they occur, rather than place them on the the Special Symbols page. I don't think it would be necessary to further explain their use on the transcriber's note page.