Wings of Entropy & Outmatch and Outlast

Hay everyone
I'm sure there is a thread about this somewhere but as a working man with not all the time in the world I couldn't find the answers I'm looking for. I would really like to know how will WoE trigger the stacks you get form OaO. Does it only trigger as a primary weapon even though it counts as dual wielding or will it switch between primary and secondary (for a few seconds on each or per attack).