How to eval an attribute containing {{}} - angularjs-directive

Question

In the following directive I'd like to eval {{selectedForApproval.length}}. This worked when it wasn't a directive, but once I put that into a directive, I'm unsure how to process the binding.
HTML: <button-large color="green" ng-click="completeWork()" label="Approve Selected ({{selectedForApproval.length}})"></button-large>
Directive:
directive('buttonLarge', function () {
return {
scope: false,
replace: true,
restrict: 'E',
template: '<button type="checkbox" class="buttonL"/>',
link: function (scope, element, attrs) {
var config = {
label: "Submit",
color: "Default"
};
angular.extend(config, attrs);
element.addClass("b"+capitalize(config.color));
element.html(scope.$parent.$eval(config.label));
//capitalize first letter of string
function capitalize(s) {
return s[0].toUpperCase() + s.slice(1);
}
}
}
})

Answer 1

The solution was to use transclusion...
<button-large color="green" ng-click="completeWork()">Approve Selected ({{selectedForApproval.length}})</button-large>
directive('buttonLarge', function () {
return {
scope: false,
replace: true,
restrict: 'E',
transclude: true,
template: '<button type="checkbox" class="buttonL" ng-transclude/>',
link: function (scope, element, attrs) {
var config = {
color: "Default"
};
angular.extend(config, attrs);
element.addClass("b"+capitalize(config.color));
//capitalize first letter of string
function capitalize(s) {
return s[0].toUpperCase() + s.slice(1);
}
}
}
})