How can the electronic cash in the local wallet be transferred to the online wallet?
Through a secred. It is a code, like this one: e1000:secret:6532891df9549377c43ca27ec326199c7dfc205d1a62fe0cf2322dabf56adcf20
The secred is created in your local wallet, you sent it to the online wallet an copy the secred in. (Or vice versa.)