Can you shared the .blend file, please? Is a good way for see what params you use for this test.
Thanks in advanced.
Here's the link for the blend file.
Thanks for shared your scene. I am very busy lately, working in the new project of TheBounty integration in Blender using C++ instead Python.
With this integration, some of the current features are improved using the same approach of Cycles.
In the past, I made an additional code in Yafaray addon to render the particles hair with UV.
Yafaray developers have ignored my offer.
I don't remember their code, but currently you can use textures with the hair. See this TheBounty test made with JuhaW user.