forwarding Ports via VPN ??

[Cestonaro Thilo <C.Thilo@gmx.de>]

Hey,

i have a vpn established and working via a Linux (Debian) Box and a
Windows with openvpn. 
The tap devices have the following ips:
linux 192.168.200.201
windows 192.168.200.202

My intern network address at linux net is 
192.168.1.0/24
and under windows it's
192.168.0.0/24

now my question:
I want to forward the ports 2005 2006 7064 from the Linux net into the
Windows net ( enough when the packets appear at the vpn endpoint in
Windows net)
I get at the Linux VPN box the packets via eth0 
these packets are send to 255.255.255.255:2005 for example.
Now I want them to go into the tap0 dev and appear at the windows box.

I tried following rules for iptable at the linux box:

iptables -A INPUT -i tap0 -j ACCEPT
iptables -A OUTPUT -o tap0 -j ACCEPT

iptables -t nat -A PREROUTING -p udp -i eth0 --dport 2005 -j DNAT --to
192.168.200.202:2005
iptables -t nat -A PREROUTING -p tcp -i eth0 --dport 2005 -j DNAT --to
192.168.200.202:2005
iptables -t nat -A PREROUTING -p udp -i eth0 --dport 2006 -j DNAT --to
192.168.200.202:2006
iptables -t nat -A PREROUTING -p tcp -i eth0 --dport 2006 -j DNAT --to
192.168.200.202:2006
iptables -t nat -A PREROUTING -p udp -i eth0 --dport 7064 -j DNAT --to
192.168.200.202:7064
iptables -t nat -A PREROUTING -p tcp -i eth0 --dport 7064 -j DNAT --to
192.168.200.202:7064

iptables -A FORWARD -p udp -i eth0 --dport 2005 -j ACCEPT
iptables -A FORWARD -p tcp -i eth0 --dport 2005 -j ACCEPT
iptables -A FORWARD -p udp -i eth0 --dport 2006 -j ACCEPT
iptables -A FORWARD -p tcp -i eth0 --dport 2006 -j ACCEPT
iptables -A FORWARD -p udp -i eth0 --dport 7064 -j ACCEPT
iptables -A FORWARD -p tcp -i eth0 --dport 7064 -j ACCEPT


Could anyone say why this is not working?
I looked at the tap0 dev for outgoing packets with "iptraf -i tap0 -u".
But there are nor outgoing neither incoming packets :(

Ciao Thilo