Forms Data Controls :: ImageButton Inside A Repeater That Is In Another Repeater & Events?

I have a user control that displays a shopping cart in an ecommerce application.

The main cart display is a repeater that renders as a html table. In one of those table columns, there is another repeater to display people associated with the products int he cart (it's a repeater in case there is a line item >1 with multiple people).

I've added an ImageButton that I want to use to change the person associated with the item. At first, when I'd click on it I was getting this error:

Invalid postback or callback argument. Event validation is enabled using <pages enableEventValidation="true"/> in configuration or <%@ Page EnableEventValidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.

So as an experiment I disabled EventValidation on the page (not the control it's self) and now I do not get an error, but I also do not ever hit the breakpoint I set in the innermost repeater's ItemCommand event.

So I wonder how I might do this without disabling EventValidation, because this control will show up on multiple pages and we don't want to edit them all. Also, I'll need to know not only the repeater containing the control's row that the event came from but also the row index of the repeater containg this one. Is this possible?