Request for a 5th payment processor configuration field

The payment processor configuration has 4 customisable fields as described in the table `payment_processor_type`: user_name, password, signature, and subject.

The payment processor I am writing requires 5 configuration fields on a per-gateway basis: username, password, encryption key, biller code and merchant id – one more than is currently provided.

I have avoided this issue by using a space delimited list to fit two variables inside one of these fields, but it would be preferable if this was not necessary for this and potentially future payment processors which need 5 or more fields.