Hello, I generate two UV Channels in The Mesh from Strands Operator. Now I want to use both UV Channels in Octane. How is that possible?

I want to use the first UV chanel to color the Hair from the Meshcolor. And the Second Channel I want to use for a Gradient from Root to tip of the Hairs.

I just dont understand how I can choose which channel I want to use in Octane.