Ubuntu Networking :: VPN Client And Samba/SSH Server On One Physical Machine?

I'd like to access a samba/SSH server which itself is connected to a VPN Server, therefore acting as a VPN Client. As soon as the VPN Connection is established, samba and ssh connections to this VPN Client get a timeout. But not all of them.

To get a better understanding I made an overview. The first one is a general network overview, without any VPN Connection, the second one with the VPN Connection established.

Network Overview without VPN
I can access the server in several ways:
*From the router via ssh (router runs ipcop with busybox)
*From the laptop via ssh (putty via Windows 7)
*From the laptop via samba
*From the internet via ssh (port forwarding to the ssh server)

Everything is working as it should.

Now the server that runs ssh and samba service connects to a VPN Server on the Internet, this is also working fine. Now it gets weird. The only samba/SSH connection that is still working is ssh directly from the router to the server. Everything else gets a timeout:
*From the laptop via ssh (putty via Windows 7)
*From the laptop via samba
*From the internet via ssh (port forwarding to the ssh server)
Network Overview with VPN active

Why is that? It seems from the little understanding I have of vpn and networking, that incoming packages (like samba request from the laptop) don't get send directly back over eth0 but over the vpn connection. This seems somewhat logic, BUT ssh from the router is still working. Why from the router and not from the laptop? I really can't get my head around it.

Configuration Overview

tldr; One Client acts as VPN Client and samba/SSH Server. As soon as the VPN Connection is established samba/SSH stop working, but only partially.