Setting up Scheduled Transaction to process loan payments

[Don Ireland]

I've read that I can create scheduled transactions that look at the 
current balance, calculate the interest and deduct it from the total 
amount of the payment.  But I'm having trouble figuring out how the 
formula works (I don't even know WHAT the formula is called or what the 
variable names are).

Can someone shed some light on the subject?

TIA!

-- 
Don Ireland