3 Level Master Detail

Does anyone ever made an apps that contains 3 level of Master Detail ?

Example :

Sales_Order :
PK Sales_Order_ID
FK Customer
… Address
… City

Sales_Order_Item :
PK Sales_Order_Item_ID
FK Sales_Order_ID
… Item_ID
… UoM
… Qty
… Price

Sales_Order_Item_Discount
PK Sales_Order_Item_Discount_ID
FK Sales_Order_Item_ID
… Promotion_ID
… Field_Lock
… Value

The problem i got is, whenever i want to use 3 level of master-detail, the 2nd Level must use “Single Record” types of form. And the form button in GRID can’t be used in 2nd level of master-detail.

Any idea how to solve or maybe better way to solve this problem ?

Thanks

Use the grid but add the new button as a link in the main form using a select field and sc_redir

Regards