Make Custom Particle Shader interact with Particle System parameters

I'm specifically interested in the "Color over lifetime" property in the particle system interacting with the shader. If you assign a default Unity particle shader to the renderer, it all works fine, but when I'm using my own shaders, the particles completely ignore the "Color over lifetime" property. This leads me to believe that all the color combinations are done in the shader. What could I do to write my own particle shaders, and take into account all the particle system properties at the same time?