[suicideneil]

I believe that the OPs charger has a suitable balancer board for dual lipos, upto 2x 4s lipos iirc. With that in mind, and assuming the charger is designed suitably, he should be able to wire the packs up either in series or parallel and then plug in the balance plugs and ht the charge button- depends how the balance board is wired up really- to see a pair of 4s lipos, or one 8s pack?

For the record though, if the charger and powersupply are powerful enough, and you have a suitable balancer, then charging in series & parallel will take the same length if time, so no real advantage either way from what I can see...