Niconico announced today that Daigo Umehara will appear in the Fighting Games Stage in its Chokaigi 2 event on April 28 (14.30 to 16:30).
Nuki, R (Guy player), Sako, Haitani, Tokido, Mago, Fuudo, Uryo, Bon-hcan, are also confirmed. A 4 on 4 exhibition match will be held for SSF4AE2012 and Vampire Savior (via Vampire Resurrection).
Umehara was invited last year for an exhibition match at Chokaigi 1.
Note that we're not sure what will happen since Umehara was also confirmed to attend Norcal Regionals 2013 which is scheduled on April 26-28. This's clearly a schedule conflict.