bug: dependencies are not tracked with the as-element="compose" attribute

**I'm submitting a bug report**

* **Library Version:**
2.0.0-rc.5

**Please tell us about your environment:**
* **Operating System:**
Windows 10

* **Node Version:**
7.6.0

* **NPM Version:**
4.1.2

* **JSPM OR Webpack AND Version**
webpack 3.8.1

* **Browser:**
all

* **Language:**
TypeScript 2.5.3

**Current behavior:**
The plugin correctly tracks dependencies for the `` but not for ``

**Expected/desired behavior:**
It should be possible to use the `as-element` in a similar way as with `compose` directly.