Payment terms configuration issue

Hi All,

I have a requirement of configuring the following AR payment terms in the system

1) 50% payment due in advance 50% due 45 days from Invoice Date

2) Payment in advance

In OME2 how to configure the above terms for no. 1 , should i use the installlment option in while config...

Please provide me detail steps for config and also let me know how to take care Advance payment part.. We dont have customer down payment option in the project scope..

Regards,

Sandip