Default [Q] how to connect android app to a specific port

Hi, i have GT-i9500 i need to connect my VoIP app witch is rynga to a server that blocks this connection
i know that the app connects by default to the port 5060 that is blocked, but i know also that there is another server on port 443 witch is open
how can i force this app to connect threw port 443 or threw a server that i can modify
does any app or simple method exist??
Thank you for any help