As a true Wooter, I know that only Sansa matters. As someone noted, you can plug your Sansa headphone-out into the Aux input to play your Sansa over these, and for a few bucks, and with Google skills aimed at the combination of the words "cable" and "jive," you can find a site that will make a connector that will enable you to charge your Sansa through the Ipod connector.
However, for reasons known only to the Sansa gods, the current Sansas will not charge and play at the same time. You can run them until they run out of juice and charge them afters. (Some with greater Sansa-fu than I have been able to connect their Sansas just enough to charge them, but poorly enough that the Sansas don't realize they are connected. They say this lets them charge and play, but such deception is too horrible to be contemplated. Of more than this I will not speak.