I have had exactly the same problem and it is a pain in the arse.
However, for only a few odd events where I have this problem the simple solution (at least for showing the map) is to simply enable the GPS dropper in Google Maps Labs, drop on a location to get the co-ords. Then search for them giving you the marker… then simply embedding it as the first line of the post and turn it off in the plugin?
Looks identical this way.
But please please make this a priority in the next build 🙂