Well here's my fist patch file about this subject.
Why the first, it's just that I want to be sure that what I'm doing fit's the need of the software. I wouldn't like to get too far to realize it shouldn't be like that.
So, what this patch does. It's to modify the "OrderTypeData.xml" to include a new CustRequestType and QuoteType.
That allows to create a request, from where you can create a quote, from that you can create a purchase order.
The request it's "Request For Purchase Quote" type
The quote it's "Purchase Quote"
Before you try to create the order from the purchase quote you have to set the next roles for the quote:
In order to set the Internal organization for the purchase order.
After that you can create an order from this type of quotes.
Besaides that, you also have to recompile the order app, since I've changed a java file.
PS. Please let me know if something goes wrong with your tests as soon as you can