Want to configure virtual server for the applications in which application is redirecting payment gateway or third party API on internet.

The problem as outlined here is not clear enough. Perhaps you could be more specific in what you want to achieve and what the situation is currently. It appears to me that all the redirection you need is embedded in the application ( handling the payment ). From the little I could glean, if users hit your virtual server and it loadbalance users to the application which then presents a payment platform and, upon success redirect to the original ( first ) site, then, you must have some checks ( some "if" statements )in the original application that checks if the user is making a first-time visit or is coming from the final payment site.

That does not have to do with virtual server or loadbalancing at all, except for the initial loadbalancing to the app servers behind BIGIP.

Maybe there is something else you want to point out?