How do I make a round or partially transparent logo for the SPG300/600?

How do I make a round or partially transparent logo for the SPG300/600?

When creating a logo file from a bitmap using the logogen.exe program, you can set the white, grey and blanking limits for that logo. The blanking limit designates a certain lightness (0-255) for which all lower (darker) values will be interpreted as transparent by the SPG 300/600. By setting this blanking level to something between white and black you can create logos of any shape. You can access these settings by choosing "Grey Level" from the "Settings" menu.