Email merge field from Product Details not working

Email merge field from Product Details not working

Hi there,
When I try to include a merge field from product details i.e. ${SalesOrders.Product Details}, on a Sales Order template, the product details do not show up in the mail wheras the rest of the merge fields are ok.

Is there a problem with merge fields from detail sections ?
Ps this is urgent as I need to give a demo soon :-)

Thanks
Andrew