* Ceremony held instead of state funeral
* Held in Agrigento, 200 km from Lampedusa
* Eritrean ambassador attends ceremony
By Steve Scherer
ROME, Oct 21 (Reuters) - More than 100 survivors of a shipwreck in which hundreds of African immigrants died burst through the gates of a holding centre on the Italian island of Lampedusa on Monday in a protest against the refusal of authorities to ...