Got it or at least a work around without purchasing a 3rd party font editor.
I imported the point shapefile representing the highway shields to a geodatabase. Each point was then symbolized with DDV style. Next, I converted symbology to representation. ( See ArcGIS Resource Center > Help > Desktop 10 search "Cartographic Representations" http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/A_quick_tour_of_representations/008t00... ) The " A quick tour of representations" helped. I'd suggest a read.
Now I can add a point location and create a new shield (representation) if it did not exist in the DDV style.