He is not asking how to recolor .dds textures, but to open the .3do model files.
shStudio does open both .3do and .dds files for viewing only, if you want to edit them I have to dissapoint you, there currently is no 3D Modelling application that supports saving as Shaiya Online.3do files, except of a converter that can (apparently) convert any 3D file into Shaiya Online.3do, which is called 3D Object Converter.