Read HTML and manage frames in webbrowser control

Question

Hey.
I have a webbrowser control in my C# program which is loading a site that is build up by frames.
So when I use webbrowser.DocumentText I only get the source of the main site where all the frames are loaded.
Futher more there are input fields in the main frame where I want to set innertext and use Invoke member at. But instead of focus on the frame, the webbrowser focus on the document where all the frames are loaded, so I get an error when I am trying to set Innertext and so on.

Is there any way that I can focus on the frames so I can set innertext in input fields, and get the source of the different frames that are loaded ?

Best Regards
Mads