Openfire files (classes) need to be edited to get & post messages from & to "ofMessageArchive" table

Hi…I want to do two changes to Openfire source code. I have to add one more column to “ofMessageArchive” table in DB. I need to fetch messages based on JID and this new column and need to insert value for this column while posting a message. Which class files I have to edit (using Eclipse) to achieve these changes? Thanks