How to add your own custom payments

First you will need to create your new payment.

Go to Sales>Manage Register Payments

Click on New Payment Method

Once you've fill out the two fields click on Save

Next, you have to add the new payment option to your register. 

Go to the System Menu > Manage Register

Edit the register you need to modify

Simply click on the new payment option and save (Note: seven is the maximum number of payments)

Open the register you just changed and you'll be able to select the new payment method. 

You'll have to change all of the registers individually for the new payment.