Backdate an "Active Date" when setting up a new Income account

We initiated a new service in our business line in 2024, and initially thought this would be a one-off business and simply invoiced this under "Services"  However, it has grown in 2024 and looks as though it will continue this trajectory going forward and become a viable business line.  So, we would like to set up a sub-account under Services (Income) for Marketing & Logistics.  No problem, except we would like to back date the account to 01-01-24, then go in manually to each invoice we have already issued (only about 15 so far, so no biggie) to fall under this new account.  Unfortunately, when setting up the new account we are unable to locate a place that we can enter an "AS OF" date for the account, which just defaults to current date meaning we can't go back and change the invocies we have already done prior to today.  We are cash accounting basis and have invoices outstanding at year end, so this really throws it off.  Obviously should have done it initially but didn't think we would continue this line.  Is there anyway to change the "AS OF" date for the account to be able to edit the prior invoices and get our P&L to capture this income properly?