Comment 4 for bug 551543

1. A pro-forma invoice is used to make a "financial offer" to the customer. If the customer agree then the order will be accepted, processed and the proforma invoice get's a real invoice.
2. A pro-forma invoice is used to give your customer a document to prepare import-export documents to calculate the total impact of a sale, before the sale is a fact.
3. Some use it as a pre-payment document before delivery (e.g. webshops) to avoid transactions before payment is received and the salesdeal is a fact. (It is miss-using this functionality as customer has no legal invoice to pay and could not accept it for payments)

In both situations one would not want accounting entries in his OpenERP system. So current build functionality does what is needed for both situations and think this is the right behavior.
It correspondents also to the many links on internet and act equal to e.g. Baan en Sap software regarding no financial transactions.
That means the doc text is wrong.