Openvpn is an possible solution for the problem of getting the broadcast packets through the VPN, because it comes with a tap device driver. Here is in short what i did to make it work:

1. i used the Microsoft Windows Server 2008 Base image (micro instance) for this experiment.
2. install the the openvpn software from openvpn.net, found here:
     http://openvpn.net/index.php/download.html
3. in the security groups settings from amazon's ec2 console add an inbound rule for TCP port 1194 (which is the Openvpn port)
4. start openvpn on the ec2 instance in passive (server) mode:
     openvpn --proto tcp-server --dev tap --ifconfig 10.4.0.2 255.255.0.0
5. start openvpn on your local machine and connect it to the ec2 instance:
     openvpn --proto tcp-client --dev tap --ifconfig 10.4.0.1 255.255.0.0

So far this gets me an additional network interface which connects my local computer with the ec2 instance. I use 10.4.0.0/16 as a netmask for the VPN which is seperate from my LAN. The local machine gets 10.4.0.1 and the ec2 instance gets 10.4.0.2 as a virtual address. Broadcast traffic to 10.4.255.255 is passed through the virtual interface.

If you use the windows firewall (by default enabled), you probably need to add exception rules to allow traffic on UDP port 11423 and various TCP ports (among them 11523-11528 and 4418) to allow Poser and the QueueManager to talk to each other. I simply disabled the firewall for the virtual interface, which is no problem because nobody else uses my LAN.

I did not use encryption or authorization with OpenVPN, you probably should use it in real life, but for trying it out this was easier.