Transparent Redirection not working


I’m trying to implement a “Sign-In with Twitter” button in my application.
I have been reading the forums and help topics for two days, trying everything, and I’m really out of ideas.

My application has “read-write” permissions. I also checked the option to allow the application to be used to Sign in with Twitter.
If I’m not logged in, I can login and be redirected to my callback URL with no problem.

The problem is that if I’m already logged in to twitter, every time I click the button to sign-in, it does not make a transparent redirect:

  • If i use /oauth/authenticate?oauth_token=abc I’m always redirected to and asked to click the Sign In button (although I’m already Signed In)

  • If i use /oauth/authorize?oauth_token=abc I’m always redirected to and asked to authorize the app, although I already authorized the app hundreds of times. Reading the API Documentation I know that is the default behavior for applications with “Read write and Access direct messages”, but again, my application is “Read Write” only.

I’m completely lost out here. Is there something I’m missing ?
Can someone give me a hint or point me in some new direction ?