did you ever figure this out

Create a product that is the parent product and set the it as stockable, produced make to stock or make to order depending on how you want the product to be deducted during sales. then create the child or children product(s) (you can set the properties to consumable, or stockable, make to stock and Buy) once you have created the child/children product(s) go back to the parent product and select BoM (Bill of Materials) and select create in the opened window. In the window that then opens, add all the child products to the BoM line product with the amount required of each child product to make the parent product. NOTE you can find this information in OpenERP guide. (Integrate your Logistic Processes with OpenERP A Simple Approach to Manage the Manufacturing and Supply Chain Complexity)