AR: Need to update on account reciepts default GL account to a new GL account

Hello Gurus,

   Really need your urgent answer on this issue. We need to update the default GL account we are currently using for On Account Receipts. I updated the account string at bank account level but its not updating the receivable class for On Account. do I have to create a new receivable class for this.. any other way to update the default accounting? it lets me update at the bank account level, its just not updating the receivable class.

  Nevigation: Setup>Receipts>Receipt Class>Bank Accounts

it lets me updates at the bank account level : setup>Banks>Bank Accounts>Receivable More Options