you can display the 1Stop Product Description rather than the order item description. In the invoice if you replace
 
[%ITEM_TITLE1%]
 
with
 
[%PRODUCT_TITLE1%]
 
etc..
 
and up to 
 
[%ITEM_TITLE20%]
 
You can use any of the other product details defined in the OSOP products. More information on the macros that can be use are shown at the following link:
 
http://www.1stoporders.co.uk/1StopOrdersDefRO.html