Please, please, keep in mind that this doesn't work 100% of the time.
If your character isn't showing up in the Keep even after a long period of time (more then 24 hours), try this:
You take the number in the very end of the link to YOUR own Dragon Age 2 profile, in this example it is "213985952", yours will be different:
http://social.bioware.com/43142/&v=bw_games&game=dragonage2_pc&display=characters&pid=213985952
and replace the number "000000000" in this link with it:
http://social.bioware.com/dragonage_profile_diagnostics.php?persona_id=000000000&game=dragonage1_pc
You have to change the "_pc" suffix into "_xbox" or "_ps3", depending on which platform you've been playing DA:O on.
If that page says you have your profile full (50 files uploaded), delete some of the Wardens then go back to the game and make a new save. The character should appear there shortly, it will take the character a longer amount of time to appear in Keep (again up to 24 hours), so be patient. Characters that have red crosses to their name won't be uploaded to the Keep. You have to delete them and upload them again.
You can find your own Dragon Age 2 profile by going to the Legacy Bioware Social Network (https://social.biowa...ntitlements.php) and selecting "My Games", "Dragon Age 2" from the left menu.