Hi,
You can achieve this behavior by modifying the MyAccount web part, please open Visual Studio and find the following file
~/CMSWebparts/Membership/Profile/MyAccount.ascx.cs, in this file around the line
1106 there is else branch which has only one line of code where is visibility set to false, to redirect the user you should modify code likes this:
else
{
// Hide control if current user is not authenticated
Visible = false;
Response.Redirect("http://somepage.com");
}
I hope this information helps.
Best Regards,
Roman Konicek