Coverting PDF page to grayscale Tiff

We are trying to produce a tiff image with a gray scale color palette. I have looked at TiffSettings closely but I am not seeing anything obvious. 

I am missing something? I could use other APIs to get it done. However, before I run down that path I wanted to be sure I was correct in my assumption that Aspose does not support grayscale tiff conversion natively.

Thanks