UPnP through a firewall, how to enable

Hi,
I have a UPnP enabled windows firewall (kerio) and a linux box with a SSL enabled FTP server. This linux box is protected by a iptables firewall and the SSL encrypted sessions can only be active.
The problem seems to be that the FTP server does not initiate a UPnP connection through the firewall.

Resolving host name *.*.*.*...
Connecting to (*.*.*.*) -> IP: *.*.*.* PORT: 21
Connected to (*.*.*.*) -> Time = 15ms
Socket connected waiting for login sequence.
{220 MOTD msgs}
AUTH TLS
234 AUTH TLS OK.
Connected. Exchanging encryption keys...
Session Cipher: 128 bit RC4
SSL encrypted session established.
PBSZ 0
200 PBSZ=0
USER *
331 User campus OK. Password required
PASS *
230-User campus has group access to: video audio dialout uucp
230- ftpusers
230-This server supports FXP transfers
230 OK. Current restricted directory is /
SYST
215 UNIX Type: L8
FEAT
211-Extensions supported:
EPRT
IDLE
MDTM
SIZE
REST STREAM
MLST type*;size*;sizd*;modify*;UNIX.mode*;UNIX.uid*;UNIX.gid*;unique*;
MLSD
ESTP
PASV
EPSV
SPSV
ESTA
AUTH TLS
PBSZ
PROT
211 End.
Detected Server Software: PureFTPd
PWD
257 "/" is your current location
TYPE A
200 TYPE is now ASCII
PROT P
534 Fallback to [C]
PROT C
200 OK
Connecting IP Repeater "repeater.smartftp.com" ...
IP Repeater returned: "*.*.*.*"
PORT *,*,*,*,15,97
200 PORT command successful
Opening data connection IP: *.*.*.* PORT: 3937.
MLSD
425 Could not open data connection to port 3937: Connection refused


It looks like the port has never been opened using UPnP. How do I enable this??