Is it possible to add recurring payments to a 'Third Party Gateway' module?

[KiprasT]

https://developers.whmcs.com/payment-gateways/subscription-management/ 'Implementing In Payment Gateway Modules' step is where my question is coming from. I am developing a 'Third Party Gateway' module for a payment processor, said processor allows recurring payments to go through even if the initial payment was processed by their hosted payment page. If i understand correctly I should be able to implement a function which runs when you click on an 'Attempt Capture' button (or a cron triggers this function), yet no matter what I try to do - the button stays disabled. Is there something I do not understand in the documentation?