ok, if i remember right, its a long time since doing those batteries, your charge rate is the battery size, i.e 1800 charges at 1.8 etc etc.
on the b6 you plug in switch on then use the battery type button to select the battery, then the status one to select charge n type, did you get the instructions in the box with that one, did hear a few who havent, if not im sure theres a download for them as well