[Dovecot] LDAP: allow pop3, restrict imap

Hello,

I have all userdata in a ldapserver. Every user has the right to use pop3. There is no explicit attribute allowing that. It's simply possible.

Now I like to add imap. For a starting period I like to restrict, who
may use imap.

http://wiki2.dovecot.org/Authentication/RestrictAccess mention a solution where I could modify ldap pass_filter. But that require an attribute
"service=pop3" to be present in the ldap servers. In my case I have to add it for
every existing user :-/ No way...

Are there other options?

Thanks, Andreas