I have the same problem,
As I know to implement DIV Integration, two important issue must be considered:
When The QVWS and Salesforce are installed in different machine we need to use Proxy.aspx to define qlikwebserver and this file is only served with dot net application so we must use Wokbench DLL and XML besides of that(As I know Your solution which is AJAX implementation works only in situation that salesforce and qlikserver are installed at same machine)
The second point is that Authentication like SSO.
Is there any practice to this issue?