Didn't try it, but since seam-security is based on picketlink-idm, It should be possible to use picketlink's LDAP identity store implementation.
The full name of the class is
org.picketlink.idm.impl.store.ldap.LDAPIdentityStoreImpland it can be found in the following dependency :
<dependency> <groupId>org.picketlink.idm</groupId> <artifactId>picketlink-idm-ldap</artifactId> </dependency>
Have you success using LDAP with seam 3 ?