About query occupant

sorry, my english is not good.

I want to query occupant with a Multi-User chat room, i use below protocol

<iq from =’ hag66@shakespeare . lit /pda ’

id =’kl2fax27 ’

to =’coven@chat . shakespeare .lit ’

type =’get ’>

<query xmlns =’http: // jabber .org / protocol / disco # items ’/ >

but this protocol only get online members in this chat room

my problem is how can i get joined this room member list?