This is a lovely addition to the series. While I am horribly curious about what will happen next in the overarching series, I was wondering about those codenames as well. I like it because you write the teenage boy banter very well and it is easy to see the camaraderie between the boys. I'm glad to hear that there are three more to come - spam my f-list with good fics any time :)! By the way, I have one correction for you:

"Bite me, Chang!" Duo pocked his tongue out at Wufei and then picked the radio again.

I believe you meant to say that he poked his tongue out at Wufei - pocked would probably be some odd thing with pocky... yummy...