Yes, the generic serial driver will make development of drivers pretty easy. However, to make a driver that has a more tight integration and can monitor state, recover from errors, and so on, still needs to be done by hand in C++.
If you want to see how it's done, click 'advanced' 'device templates'. Add the manufacturer if it's not there, and the model for the device with the rs232 interface. Be sure the category of device is interfaces/lighting or interfaces/specialized.
You can see our own CM11A device and how this works as a template. Make note of the device template ID. Then in /usr/pluto/bin run DCEGen -d [device id]. That will create a C++ program for you that's ready to compile and implement. If you add commands, data or events to teh device template, just re-run DCEGen and choose "merge" to merge in the new code with your existing project.