I will share my experience on that: I thought is not possible ,and I was about to discard my old joomla 1.5 ,but I'm glade to share it with everyone here
backup-backup-backup
login to phpmyadmin
select old joomla database for 1.5
select tables starting with js_discuss
export them
==
open the new joomla databse
import the tables u extracted
install easydiscuss
I successfully made it ,however I STILL CAN'T LINK EASY-SOCIAL PROFILE ,even if it s enabled in setting,every time I click on easy-discuss profile -DOSE-NOT redirects to easy-social
backup-backup-backup
login to phpmyadmin
select old joomla database for 1.5
select tables starting with js_discuss
export them
==
open the new joomla databse
import the tables u extracted
install easydiscuss
I successfully made it ,however I STILL CAN'T LINK EASY-SOCIAL PROFILE ,even if it s enabled in setting,every time I click on easy-discuss profile -DOSE-NOT redirects to easy-social