Nope, the icons to display about the city bar are returned as a string where each Unicode character denotes a font glyph in the font file. Since the map-drawing code is in the EXE there's no way to mix . . . well, maybe there is.
You can embed image files in text strings using BTS's xml-like format, but I've never tried it on the city bar. I think you're far better off just getting the glyph in that font file. Is it not present in your file? Have you opened it in DXTbmp?