Hi, I've uploaded a zip file containing the buoys modified for IALA region B to
http://www.bridgecommand.co.uk/file/IALA_RegionB.zip
If you download this, find the 'Buoy' folder in the 'Models' folder in your Bridge Command installation folder, and replace it with the one from the .zip file.
In Bridge Command, all of the ship and buoy models are 3d model files, so you don't need to make any changes to the source code itself. To make these changes to the buoys, all I have done is changed the colour in the model files.
If you want to change the colour of the lights, find the 'world model' you want to change, and open up the light.ini file. For each light, you will see some settings like this for a red light:
Red(1)=255
Green(1)=0
Blue(1)=0
Since all red and green lights should swap colours, you can change this to a green light.
Red(1)=0
Green(1)=255
Blue(1)=0
If you swap all red and green lights, the world model should now be set up for IALA region B.
Let me know if you have any questions about this.