Assigning Users to Groups on LDAP thru EP

Hi,

I have configured EP6 SP7 with multiple LDAP(MS-ADS)servers. I can read/write the groups and users to LDAP through EP. But i cannot assign the users to groups through Enterprise Portal. Also if i assign users to a group in LDAP on LDAP server itself, these assignments does not show up in the portal. do i have to configure my dataSourceConfiguration_multiLDAP_db.xml file? if so then which parameter?

Please advise.

regards,

Hassan