problem with set=setspec

["Mirko Grava (ML)" <ops@klez.it>]

I need some help about this:
Is it possible write something like this in acl?

access to dn.regex=".*vd=([^,]+),o=hosting,dc=example,dc=tld$"
        by self write
        by set="user/editAccounts & [TRUE]  vd & [$1]" write
        by set="user/editAccounts & [FALSE] vd & [$1]" read
        by * none

Or the pattern for set is only a single attribute?
TIA

-- 
Mirko Grava (ML) <ops@klez.it>