Overriding a salesforce related list Add" button"

I’m trying to override the salesforce MultiAdd action for OrderItems. When I’m viewing an Order, this is the “Add Products” button on the OrderItems related list view.

So, I create my skuid page, which needs the Id of the Order as a url parameter. I have to know what the Order is to add OrderItems.

I create a Visualforce page like so:

<apex:page standardController="OrderItem"
  extensions="skuid.Redirects"
  action="{!redirect}&amp;page=AddInvoiceServices">
</apex:page>

The standardController for the vf page has to be OrderItem if this is going to be an override for an action on an OrderItems related list.

But I need to pass an Order id, not an OrderItem id… so I get this…

Id value 8012A000000ml7y is not valid for the OrderItem standard controller