How to use Web Lookup to search a webiste that requires a login (username/password)?

I love Web Lookup, great tool. 

I would like to search a website that requires a login (username/password).

Is this possible with Web Lookup?

If  yes, what do I have to do, or where can I find the info on how to do it.

If no, are there any plans to implement such a feature in the (near) future?

Best regards

Siegfried