Thank you for trying to make drivers for logitech keyboards.
I have a Cordless Desktop Optical Black model ( http://www.logitech.com/index.cfm/downloads/software/US/EN,CRID=1797,contentid=8055 )- I haven't tried your driver yet because I actually wanted the OSD function more than anything else.
All the programmable function keys seem to be doing what I want but as logitech didn't use LEDs on the keyboard, I don't get an indication if CAPs lock is on, the same for volume, I would like an OSD for volume.
Keep up the good work, it seems that IF logitech make drivers it will be part of the new application they have - 50MB for an app to make a keyboard work!!!
cheers from Australia