[Dovecot] sieve redirect envelope address problem

Good day!

I have a problem with mail redirection through sieve rules. I've configured sieve rule that redirects any mail coming to user to gmail mailbox (or whatever external mail system there is). But when sieve redirects any mail it puts vmail@%dovecot_hostname% into envelope address, gives it to my exim for delivery and gmail rejects my mail because user vmail@%dovecot_hostname% do not exist. Please, advice for what can be done about this behavior.

my doveconf -n http://pastebin.com/0dyL9Jgs

Thanks in advance!

-- С уважением, Костырев Александр администратор Linux-систем