You can post them but just providing the url or if you want to use the eBay widget and display them like this:-
To do this simply press the eBay logo in advanced posting and a pop up box will appear. In the pop up box enter the CATAGORY not the Item number. 99% of Cars Diecast are listed under the catagory 'toys & games' so enter that into the pop up box.
Then all you need to do is add the item number between the bb code
Please post if you have any problems doing this