We or you, would have to write a shader to build in the refractive ability. But you may need to pass certain params and properties from code like you mentioned.
We have been planning on implementing the ability to pass properties and values to the shaders from LUA script as the end users obviously don't have access to c++ at the current time.
I have tried through various modelling programs, but they can't export the Refractive Index bit. I've also checked the Ogre forums and found some stuff, but it was talking of multiple passes, blitting to the buffer etc. and I haven't quite got my head around that yet
we can already use multiple pass, just as our base materials do. As for blitting to the buffer, you will most likely need access to code, or as stated above; lua scripts.
Its not something we could pull off immediately, but its one of those things that we ourselves would like to do.
The only problem with the with refractive shaders, they can sometimes be very expensive on performance.
Heres a link to a shader version:
http://www.ogre3d.org/forums/viewtopic.php?f=1&t=70919at the near bottom, there is a cg shader and material. Maybe worth a try if possible
Edit: you could always use a cubic texture and apply that to the material by using cubic_texture instead of texture in the .material file. If the material has custom shaders, then you will need to add the cubemap algorithm to the shader.