Track ecommerce delete item from the cart

Hi ,

Can anyone please tell me on how to track items deleted from the cart using addecommerceitem and trackEcommerceCartUpdate tags?
I find no luck here… i tried passing as follows

piwiktracker.push([‘addEcommerceItem’, “prodSKU”, “”, “”,"",""]);
or piwiktracker.push([‘addEcommerceItem’, “prodSKU”, “”, “”,"",0]);
or piwiktracker.push([‘addEcommerceItem’, “prodSKU”, “”, “”,"",-1]);

where last parameter specifies “quantity”. but it doesnt update the column deleted to 1. Kindly help.

-Regards,
Aneesha