C# Animate Secondary "Detail" Maps Offset value

I’m using this code to animate the offset value of the main texture.

render.material.mainTextureOffset = new Vector2(0, offset);

But I can’t figure out how to animate the Secondary “Detail” Map in the material. How do I access the offset value for that texture?

I’m scrolling the texture coordinates to simulate waves on a water surface.

Thanks for the tip. I found some information about that, however I also found that the second bump map is not supported on mobile devices, and that is my target platform.