In the download section http://code.google.com/p/minoposd/downloads/list you can find a zipped config tool and the hex file.
After unzipping the config tool you can use this tool for updating the minOPOSD firmware and configuring the MinimOSD for your needs as described here http://code.google.com/p/minimosd-extra/wiki/Config_Tool
Please carefully read the first 6 chapter of the 'Using Config Tool' documentation of the upper link, especially the 'Set screen change' part, and configure it to your needs.
Please remember, not every panel is portet 1 to 1 compared to MinimOSD-Extra.
The Battery Percent panel is used for showing the consumed mAh.
The following panels are not supported:
Center
HeartBeat
WP Direction
WP Distance
AirSpeed
WindSpeed
Tune
Efficiency
CallSign