Cisco VPN through a Checkpoint VPN-1 Edge

[foobar.li]

Hi out there

i have trouble with establishing a vpn connection from a cisco router through an checkpoint edge.
to avoid trubles with the roule base i've granted full access to the vpn gateway for the router.
but anyway the router cannot establish the vpn connection. In the log i get the following entry:

SmartDefense Block Reason: Incomplete packet

Even if i disable all SmartDefense related things via the cli this Error appears. please help me to solve the problem.

Further information:
it is not possible to establish the connection via the edge because this is a third party router which connects via certificates. and the third party creates no certificates for devices which are not under the control of them.

so if anybody has an idea or even a solution it would be nice ;-)

sorry for my bad english it would be easier to write in german :-D

Thanks a lot for your help

Julian