Did you try using the POI Loader app (free download)? You have to manually create your GPI file, and in the source folder have your bmp's and .gpx / .csv files when you're doing that. The image and POI filenames have to match, ie. USA_CAMS.gpx & USA_CAMS.bmp, for them to be merged into the file, if you don't follow this, you'll get the default dot or whatever for the camera.
Nokia 5800 Speed camera image
