Parameter mapping warnings

I am using sp12, and am wondering if something has changed with parameter mapping, because I am using the same method I used when I was on sp9, but am now getting compilation warnings about my parameter mapping.

I have an action with a string parameter. I bound the onAction property of several linkToAction elements to this action, and set up the mapping in the doModifyView method (retrieving each element by name, casting them to IWDLinkToAction objects, and calling addParameter to add the mapping). It builds and runs ok, but shows two warnings for each UI element I have mapped this way:

1) UIElementEventBinding onAction: Parameter <paramName>(string) cannot be supplied

2) LinkToAction <elementName> [onAction]: Action and event are not compatible

Any ideas on what I'm missing here?

Thanks,

-Dave