Mixed (Analog and Digital) signal USB interface
The original intent of ID pin on mini/micro 5-pin connectors was to discriminate host from device on "dual-role ports", formerly "OTG ports". If ID is shorted (in cable side), the port must act as host. If ID is open, the port must act as USB device.

Intermediate resistance on ID pin is reserved for other uses of the port as audio outputs in so-called "Car Kit" application, or "accessory" (not sure what does it mean), or as UART debug port. Some IC supporting optional port features use 140k as the optional value, some 102k, it varies. These specifications are not openly published, so it is difficult to say. The value of 68k could be proprietary for the Samsung camera, and might not work for others. I am quite sure that if you use open collector (or open drain) output from your digital controller to emulate push switches, the design should work just fine, provided that your camera recognizes the ID=68k.

Addition: there appears to be a patent from Fairchild for this kind of control. Many cameras as Sony, Nikon are using something similar.