In case there still is life here, I have to ask the following question.

Server is a NW 6.5.8 with latest patches and with BM 3.9.2 for Firewall and Proxy running fine.

During server-install vpn was not added, but is needed now for site-to-site-connection. I ran through the installation from BM 3.9.1 with additional vpn and added SP 2 and IR-patch afterwards. But still there is no vpncfg.nlm i.e. in the \system-path.

I put the server back to the pre-installation-state (thanks esxi/veeam).

Any hints on how to do get this done are highly welcome.