Oil Leaking from turbo

[Kevin.A]

I'm leaking oil from the top oil line right around the copper seal on the turbo itself.
What can i do to seal this?
I've replaced the line and the copper rings(twice). Can i put some high temp RTV on it? or is there someone else i can do to stop it from leaking,
On long highway journeys I have a burning oil smell in my car.

Thanks in advance for your help.