From apple's documentation it is possible to offer free trials to users, after which they will be auto-billed at the end of the trial

> 
> If you offer a free trial, it will begin when a user subscribes. They
>  will be automatically charged when the free trial is over, unless they
>  have turned off auto-renewal. If you choose to offer a free trial, a
>  drop-down menu will be displayed that will allow you to select the
>  free trial duration.
> 
> 
> 

<http://developer.apple.com/library/mac/#documentation/LanguagesUtilities/Conceptual/iTunesConnect_Guide/13_ManagingIn-AppPurchases_Robert/ManagingIn-AppPurchases.html>

Now i don't see this option available when i create a new auto-renewing subscription.

I see a screen like this as shown in docs
![enter image description here](https://i.stack.imgur.com/88IUH.png)

Does someone know where to enable this or is it even possbile? 

Or do i have to manually develop the feature by saving the free trial start date?