Regardless of the ActiveX component, it must just pass some kind of token to the server to accept the authorisation, and it seems that the authorisation is static as you already implemented a solution using Proxomitron. So all you need to do is figure out this data (try Wireshark) and send it yourself using Qt network classes. Typically it will be sent as some kind of GET or POST request, SSL-free, with perhaps some custom encryption or obfuscation by ActiveX object (which you don't care about as you only want to login as one particular user).