Sorry, I just want to get this clear, as I am pretty sure I have it right but I think I am misunderstanding what you just meant.
My Feynman diagram has a c [tex]\rightarrow[/tex] d and in that process it emits a W+. This W+ then decays to a u and anti-s. I thought charge is conseved overall in this. I wish I could show you my diagram! (also the anti-u is unaffected in the decay and continues across)