dovecot - Jun 2012 - specifying home/sieve/sieve_dir relative to mail_location

With 1.2, is it possible to specify home, sieve and sieve_dir relative to
mail_location?

I have
	mail_location = maildir:/import/mail/%n/:INDEX=/var/db/dovecot/indexes/%n
and, in the plugin section,
	home = /import/mail/%n/home
	sieve = /import/mail/%n/dovecot.sieve
	sieve_dir = /import/mail/%n/sieve
I would like to partially move users to another location (different file server)
by using an LDAP entry.
I know it's possible to specify everything relative to home, so I could
probably use relative ~/../-type paths for  mail_locatin etc., but that looks a
bit awkward.

The VirtualUsers/Home Wiki enty contains an example for relative paths
	user_attrs = .., mailDirectory=home=/var/vmail/%$
which I do not understand.

> With 1.2, is it possible to specify home, sieve and sieve_dir relative to
mail_location?
No-one, this one?

Too simple? Too stupid? Too obvious? Not possible?