Los Llanos, Venezuela

I'm wondering if anyone knows of a good, reliable private guide for the Los Llanos portion of Venezuela. I am hoping to score something similar to my wonderful guide in the Brazilian Pantanal and my goal is to photograph the critically endangered Orinoco Crocodile, along with perhaps a Green Anaconda. Anyway, I have searched on google and have only found companies that either seem too commercial or too unstable/not responding to emails. Thanks!- Brandon