FB50 and FBCJ

Hi All ,could any one Please explain me about Petty Cash Set up transaction in FB50? and later FBCJ Cash Journal,If I am not wrong we add amount to Petty cash account by Dr and Bank Cr,later during FBCJ we do Cr Petty Cash and Dr some Business Transaction Expense,but if Petty cash Account is " Post Automatically" how can I do FB50 Transaction as Dr for Adding Amount from Bank? and in FBCJ do I need to use Petty cash Account or Bank Account in "Cash Receipts" Tab?

Your Feed back greately appreciated,

Thank you ,

Sandhya,