Require 'Alias' field when entering first address / adding one while in check-out process. (PS 1.7)

[Apury]

Hello there! 

I've already taken a look into FormField.php and CustomerAddressFormatter.php and couldn't quite figure it out. 

What I'm trying to achieve is:

• To display the 'alias' field while a customer adds his first (or an following) address via checkout. As of now that field is only visible if editing an address in the 'your account' page.
• Make the 'alias' field required. 

Given that the difference in fields between adding an address outside of the 'your account' page and the one in the account-page equals 10 vs. 11, I figured there must be two different .php files and that the adjustment must be relatively quick and simple. However, after spending 7 hours on it so far, I figured I'll ask for help.

[Apury]

After some further search I found the address-form.tpl to contain the relevant section. I now got the alias to show in the desired spot. What I'm now struggling with is making it be required. I suspect CustomerAddressFormatter.php to be the relevant file.

[Kiona]

Hi,

Where and what exactly did you enter in the address-form.tpl?

I would like to have the alias field visible in the checkout, but I cannot find what kind of code and on where it should be set.

Thanks already,

Kiona