adding .bmps to preloaded POIs


I've looked for this and wasn't able to find anything about it. I have a nuvi680 with preloaded Ford dealer POIs on it which I would like to add the Ford.bmp icon. Is there a way to do this?

Just want to get to where I'm goin'

I don't think so but...

nüvi 680, nüvi 770, Garmin Mobile XT, etc...