http://www.nissindigital.com/i40_spec.html
"For Canon, Nikon, Sony DSLR System, 4/3 & Fujifilm mirrorless System"
Ony Pentax is not supported and Nissin had no interest to make a Pentax variant for their products! The reason behind must be sound..
Congrats, Pentax! It is noted that Leica is also not supported and hence Pentax has succeeded to become a Leica! That must be great and a really good news for Pentaxians! :-o