The short answer is that you can't do that.
The longer answer goes something like this,
Mendix apps are single-page web applications. The presentation of a form is based on the session, the state and the context in which this form is presented. In other words, forms do not have a URL corresponding to their possible states. The state transition from one form to another is handled internally by the client.
As Bart mentioned, there might be a way to work around this with the 'deep linking' App Store module.
You could use the deeplink module in combination with a calculated (microflow) attribute that contains the deeplink ('http://....') needed.