Using Custom Forms to Create a Record

Hello!
I am trying to create a new custom payment record, however, I have to use a specific custom form previously created in the NS administration site, I am using this way to call the custom form in my record creation:

payment = record.create({
                type: record.Type.CUSTOMER_PAYMENT,
                defaultValues: {
                    entity: xxxxx,
                    customform : "160"
                }

Is this the right way to do it?

Thanks a lot for the help!