Redmine

I am trying to use this LDAP filter (&(objectCategory=person)(objectClass=user)(!userAccountControl:1.2.840.113556.1.4.803:=2)) that does three things:

• Object is a person
• Object is a user (avoidign contact entries)
• Object is not disabled (disallowing disabled users from loging)

It seem redmine has a problem with the (!) to avoid the disabled objects, when removing it, the filter is accepted.
For now I'm leaving it out, but I'd like to fix the query.

Any ideas?