IOS5 Twitter sign in won't authenticate on my iPad, works fine on my iPhone.

I have both an iPhone 4 and an iPad1. I've installed IOS5 on both devices, and on my iPhone twitter authentication works flawlessly both in the Twitter app and in the OS wide twitter integration under settings. On my iPad however, sign in works flawlessly in the Twitter app, but the native OS twitter integration refuses to authenticate. The exact error message I get is "Error Signing In" and the body text "The user name or password is incorrect.". This comes up instantly when I press "Sign In".

I previously ran the iOS 5 betas on my iPad, and had the same issue then (twitter account under the iPad settings would not work). I assumed this was something that would be fixed for the final version. However after doing a full factory restore through iTunes to get the public and live version of IOS5 (build 9A334) on the iPad - the issue remains.

Naturally I've tried to re-enter both the user name and password - by now probably over a hundred times. I am quite sure it's not a type-o. And the credentials work on all other twitter apps I use both on the same device and on other devices - and also in the native iOS5 twitter feature on my iPhone that is also running build 9A334 (also updated using iTunes normal update procedure).

It's an iPad (first gen) 3G, 16Gb. I've tried both over wifi and over 3G (wifi disabled). I've tested using both swedish and english keyboard on the iPad (however there are no differences in the user name or password between those character sets) - just to make sure there's no problem with character encoding of the password field or something equivalent.

Could there be a cached faulty authentication token (or cookie) that was transfered over as I restored my freshly installed iOS5 from the iOS5 Beta 7 backup (to get my settings and apps e.t.c. back)? I never got it to authenticate even once on any of the betas (I started on beta 4). If so, would there be any way to clear this other than restoring the iPad to factory default and set it up as a new iPad? Naturally I want to avoid manually reinstalling every single mail account, calendar, app e.t.c. I also would like to avoid losing all my save games on the games I have lots of hours invested in, and internal data for other apps. (But that data is hopefully stored in my iTunes for each individual app so I get it back if I sync them one by one?)

Googling the error message: +"error signing in" +"the user name or password is incorrect."

Gives me 7 hits, all are related to MSN Messenger, and nothing at all about twitter or iOS can be found. The same search on Bing gives me 2 hits (both included in the previous google search). So this does not seem like a common bug/issue.

Any help would be appreciated.