Like many tradesmen I get calls from companies offering to provide this service.Obviously there is a charge involved and from what I have heard there are a number of hoops to jump through.Am I reading your post correctly that you want to do a DIY version?! Either way,I think it is more for companies rather than sole traders.If customers mention the possibility I suggest they research the difference between this and paying for it upfront.If this the only way they can or want to do it ,they are not my sort of customers.