Проверь, вероятно нужно указывать название параметра, а не только его значение...
[spoiler title=параметры использования плагина]
/**
* VirtueMart Show-Product-Snapshop Mambot
*
* <b>Usage:</b>
* <code>{product_snapshot:id=XX,showname=y,showprice=n,showdesc=n,showaddtocart=y,displayeach=h,displaylist=v,width=90%,border=0,style=color:black;,align=left}</code>
* string sku (product_sku) for more than one, separate with vertical bar
* string showname (show the product name? y or n)
* string showprice (show the product price? y or n)
* string showdesc (show the product short description? y or n)
* string quantity (the quantity to add to cart. Separate with vertical bar when there's more than one product eg 1|2|1)
* string showaddtocart (show an "Add-to-cart" link? y or n)
* string displayeach (the horizontal or vertical orientation of the product attributes. h or v)
* string displaylist (the horizontal or vertical orientation of the products.
It only applies when there is more than one sku. h or v)
* string width (The width of the Table element)
* string border (The value of the Border attribute of the Table element)
* string style (the value for the style attribute of the Table element)
* string align (defines the align of the table with the product snapshot)
*/
[/spoiler]
И еще, проверь, включена ли опция обработки контента магазина мамботами. Эта возможность появилась в VM1.1.0...