GOOGLE Earth File Converter

I need a converter to convert Google Earth (latest version 5.0) KML files into my Magellan Explorist GPS file format. That's all! The input for this system is the KML file, the output should be? the GPS .log and .upt file format. I have attached the GPS file formats for both POI and Tracks. The converter should? convert both track files and points of interest (POI) files. Programming language and application type is completely? up to the coder as long as the converter? is doing the job!