AngularJS Form Validation Directive $setValidity on element

I'm trying to use $setValidity on an element in a directive. All the examples I've found seem to set it on the controller...

I forked a JS fiddle on Form Validation and have tried a bunch of things. Any insights would be most appreciated: http://jsfiddle.net/thomporter/pmKpG/2/

In the fiddle, the $setValidity is called on the controller:

ctrl.$setValidity('pwd', true);

I'd like to do something like:

elm.$setValidity('pwd', true);

so that in the form I can do something like:

ng-class="{error:form.password.$error.pwd}"

I figured it out... You have to have a name on the input elements. As soon as I added the name, the errors were automatically bound to the elements as desired, no additional changes needed!

<input ng-model="password" name="inputPassword" class="immediate-help" password-validate required type="password" id="inputPassword" placeholder="Password">

http://jsfiddle.net/thomporter/pmKpG/4/