I tried to get a Rayleigh scattering effect by adding together volumes on different channels, inspired by the fake spectral rendering done by adding together different glass materials. A neutral volume in this method looks like:
{F277270}
Changing the different densities works like one would expect:
{F277272}
However, anisotropies seem to only affect the final luminosity, and don't seem to be added together correctly:
{F277275}
The same happens when using OSL volumes.