If your charger isn't designed to charge at 2c for your pack mah, you are asking for trouble. You will get away with it for a while, but the law of average's will get you in the end. After all, we're only human. Don't get me wrong, I'm not saying that you can't do it, but should you do it?
Don, The charger in question (The ORION ADVANTAGE Carbon Edition) is designed for this battery - has the proper settings...and works really good...
If you watch it when you are charging (the 3200's batteries) the amperage stays at 6.4 amps until the voltage hits 8.4 volts, then the amperages starts dropping quickly for that last 5% or so of the charge until the amperage just falls to nothing.
...something to remember if/when doing the 4800 packs... It contains MORE cells than the 3200 packs do. So unless I'm mistaken, even if you set the charger to 9.6 amps...I believe you have to break that amperage down per cell to see what each battery is actually taking.
With the 3200's having 2 cells, @ 6.4 amps, I believe each cell is only receiving 3.2 amps per cell. On the 4800's, where it has 4 cells, I believe each cell is only receiving 2.4 amps per cell (which would make sense, because I believe each cell in the 4800 pack are 2400 mah batterys)