When composing a message, I can easily add recipients from the personal address book, but not from the LDAP address book.
Also, I can search the LDAP addressbook, choose a single entry, and easily start composing a message to that single address. If I want to send to more than one contact, there doesn't appear to be an easy way to do this.
It would be nice if there was an "Add from address book" button on the compose screen that allowed me to search contacts in any address book and add them to the current message.