Creating a Custom Payment Term

Creating a Custom Payment Term

Hi..
I'm trying to add a custom payment term to my invoices. I tried following the instructions given in amministrazionentw's (Filippo's) previous post but I don't seem to be getting anywhere. I want to add a term value "Ship on Receipt", so that it shows up in my drop down list of terms to select. (For customers who have already sent a check for their goods.) Can anyone help me with a detailed step by step on how to get the job done?
 
TIA,
Barb
artgalstudio