Cashflow model

I need a couple of formulas for a daily cash flow model 1. A formula for payment date based on a variable (see cell B9) for credit terms. Example if the supplier has 3 day credit term the delivery on 4/2/2013 (cell C9) would be payable on 4/5/2013 (cell F11). I would like to be able to adjust cell B9 based on the credit terms of different suppliers and to have the capability to have at least 14 days as options (multiple if statements ?). The next issue is that if the due date falls on a weekend (Sat & Sun), or a federal holiday (see row 6), the payment will occur on the next business day after a weekend or a holiday. 2. We have recurring expenses that are due on certain days of the month (see Cell B15). Like the prior formula if the payment date falls on a weekend or holiday the payment will occur on the next business day after the weekend or holiday