[9.004-34] Email Protection and 6to4 support outbound?

I have set up 6to4 on our UTM 9.004-34 to test IPV6.

Inbound mail connections are now IPv6 capable, but outbound mail connections always use IPv4 even if the destination has IPv6 capable mail servers.

Here is an example sending mail from UTM with 6to4 enabled to a freenet.de Email address:

exim-out[25074]: 2012-12-26 13:02:31 1Tnpgs-0006WO-9M => ***@freenet.de P=<me@mydomain.org> R=dnslookup T=remote_smtp H=mx.freenet.de [195.4.92.9]:25 X=TLSv1:AES256-SHA:256 C="250 OK id=1Tnpgs-00087d-Vl"
exim-out[25074]: 2012-12-26 13:02:31 1Tnpgs-0006WO-9M Completed

Thought freenet.de offers IPv& on their mailservers:

# dig freenet.de MX +short
1 mx.freenet.de.

# dig mx.freenet.de AAAA +short
2001:748:100:40::8:112
2001:748:100:40::8:110
2001:748:100:40::8:111


Is it possible to send via SMTP using 6to4?