Hey there, 

I used to think this was not a problem, but that was only because I had ported my number from vf-xt > 2degrees... being able to register/authenticate my facebook account with my 022 number is pretty much impossible. 

To suggest to facebook:
http://www.facebook.com/help/contact.php?show_form=carrier_suggestions

 And you can always try the one-way international SMS number for twitter...+44 762 4801423