Do you have more detailed documentation on accessing the GrovePi sensors via serial as outlined here -> http://www.dexterindustries.com/GrovePi/engineering/software-architecture/
Can you give a bit more details on which Serial Sensors do you want to test with the GrovePi.
Right now there are two options to integrate the Serial Sensors with the GrovePi. You can either connect them directly with the Raspberry Pi Serial and write a library in Python or any other language to make it work. The other is to add code in the GrovePi firmware so that the GrovePi handles all the Serial communication and sends the data to Raspberry Pi via I2C.
We don’t have any example for the Serial Sensor, but we’ll be happy help you get the Sensor working with GrovePi and integrate the code with the Library.
What are the “Serial sensors” you mention ? Are they only a subset of all the sensors you have tested. I would like the sound, temperature and light sensors to be looked at first. See my other reply in the Forum on what is meant by Serial sensors.