Extend angular function filterFilter without altering source?

I've modified angular's function filterFilter so I can use exact matches. So searching for '1' gives only '1', not '11', '12' etc.

function filterFilter() {
  return function(array, expression,exact) {
  ...
    var search = function(obj, text){
    ...
      case "string":
        return exact?('' + obj).toLowerCase() === text:('' + obj).toLowerCase().indexOf(text) > -1;

Now I can use it like this: sectionDicts | filter:{id:section.sectionDictId}:true

But how can I extend this function without modyfying angular's source? I've found this How to extend or override existing filters in angularjs? but it's another case I think.

Also this https://groups.google.com/forum/#!msg/angular/v-WjFF-iR88/XSXRhkGhf_sJ doesn't work

Edit As suggested I've added new filter. I just copied filterFilter, modified it to my needs. Although I also had to copy functions getter and isFunction from angular.js