I am building a CPQ type tool. So the User can configure the Products they need via some Custom VF page. Then when they have done this I want to direct them to the standard Opportunity Edit page which they are familiar with. I dont want to re-create this in VF. The standard edit page will allow them to Save. Obviously if I direct them to the standard Edit page I will lose the Product configuration as this is stored in a Custom Controller [RAM] and not yet written to the DB.