Manually add a transaction to order?

I have created my own non-creditcard payment module/option.

My customers transfers money to my account via Bank transfer and marks the payment with a unique string that identfies the order.

When i import the transactions from my bank, i need to update my orders with the incomming payments and mark them as "in progress or ready to be shipped"

How would you approach this?

Thanks.

You can edit Order in back end, it is supported good enough for that

This needs to be automated on file-import.

It 's too special requirements, I think you need to develop the import function to use for it.