Just a free subdomain

I'm using the WHMCS Provisioning plug-in to allow users to purchase sites and domains and (afer some teething problems) have that setup and working nicely.

On the domain selection page, they get the option or registering a new domain, transferring an existing domain or using a free subdomain - just as it shows in the documentation. All is good :slight_smile:

But in order to encourage users to purchase, I'm also offering a time-limited trial. That's easy to do in WHMCS, I've just created a second 'product' which is 'free' and has 'Auto Terminate' set to the number of days I'm allowing the trial for.

But for the trial, I really don't want users to register/transfer domains - just use the free subdomain option. But if I un-tick 'Require Domain': 'Tick to show domain registration options' I also loose the option to allow the user to type in their own subdomain.

How do I get this bit (the ability to select a subdomain) back?