Depends whwre you are. I got mine in the UK from "KustomPCs". 160w pico. Got a 6pin to 8pinEPS adaptor coming woth a pigtail attached to power the pico and the mobo from a 6pin cable off my server psu.
Did you get the pig tail from them also ?, i ordered a pico from ebay but i'm still looking for the pig tail
Check your PM.