MRP in planning worksheet

Hello Navision users ,

I created a production order of a FG item, with 2 items in its BOM, and I don't have those 2 raw materials in my inventory , so I'm supposed to have a suggestion of a purchase order of those items in the planning worksheet , but I don't have them. I don't know what is the problem , because when I created a new purchase requisition and calculated the planning the items showed in purchase requisition , I don't know why they don't appear in the planning worksheet . 

thank you