Hi everyone. Our customer has a somewhat complicated price structure; I would like to show some extra pricing information in the multi-line add product screen, so that the salespeople know the pricing for different quantities of products at the moment of first entering the quantity.

My first idea was a "before insert" Apex trigger that fills a read-only field with the possible prices for a given client and product, and add this field to the screen - but it turns out when the user reaches that screen, the line items have not been inserted yet, so the tigger does not fire and the field stays empty.

Next I tried a simple formula field, maybe to show a field from the PricebookEntry object - but apparently you cannot add formula fields to the multiline layout. No custom buttons and links either.

My first question is: is there a really simple way to achieve what I want, that I am missing?

I searched around the web a bit, and it seems the only solution for similar cases is to use a custom Visualforce page; but it is not possible to override just the "multiline layout" step of the process. I would have to override the Add Products button from the Opportunity Products list view, and that would force me to replicate in Visualforce the full Add Products process, including the search and select product functionality from the previous step.

I am new to Visualforce and this seems like a bit of a big thing to start with, so my second question is: can I find somewhere a specific example of  replicating the Product Selection screen in Visualforce?

Thanks in advance.