[Openswan Users] plain IPSEC -> L2TP

[Wolfman]

Hi,
I finally got a working IPSEC Connection using the IPSEC Toolst from Markus 
Müller.
Now I want to change it into some more comfortable thing, using L2TP, so I 
can use it like an "dial up" connection.
Whenever I trie to connect with the Network assistant, I get the following 
error:

Apr  5 00:54:04 Linuxserver pluto[17456]: "p2n"[2] 192.168.107.123 #1: 
transition from state STATE_MAIN_R2 to state STATE_MAIN_R3
Apr  5 00:54:04 Linuxserver pluto[17456]: "p2n"[2] 192.168.107.123 #1: sent 
MR3, ISAKMP SA established
Apr  5 00:54:04 Linuxserver pluto[17456]: "p2n"[2] 192.168.107.123 #1: 
cannot respond to IPsec SA request because no connection is known for 
80.137.27.201[<some certid>]:17/1701...192.168.107.123[<some certid>]:17/1701

since my plain IPSEC Connection works withoutthis error,  this is strange, 
because it should be nearly the same IPSec stuff before handing the 
connection over to the L2TP.
So does someone got an Idea what to do? Any hints how to solve this? I red 
nearly every HP about this, but I only get configurations for IPSec/L2TP 
with PSK or plain IPSec with Certificates. Since the Certificate solution 
is the only one working here, I need IPSec/L2TP with certificates.
Here my config:

config setup
         nat_traversal=yes
         interfaces=%defaultroute
         klipsdebug=none
         plutodebug=none
         uniqueids=yes

# Add connections here.

conn %default
         keyingtries=3
         compress=yes
         disablearrivalcheck=no
         authby=rsasig
         left=%defaultroute
         leftid="<some CertId>"
         leftcert=VPN-Gateway-Cert.pem
         leftrsasigkey=%cert
         rightrsasigkey=%cert
         pfs=no

conn n2n
         right=%any
         auto=add
         leftsubnet=192.168.107.1/255.255.255.0

conn p2n
         right=%any
         auto=add