VPN with iphone/ipad

Hi,

i tried to set up a vpn between an ipad and a linux server, following
this website: http://en.gentoo-wiki.com/wiki/VPN_iPhone_IPSec

When i try to connect i get the following messages in the syslog:

Jan 27 17:53:10 vivaldi racoon: [192.168.100.216] INFO: Selected NAT-T version: RFC 3947
Jan 27 17:53:10 vivaldi racoon: INFO: Adding xauth VID payload.
Jan 27 17:53:10 vivaldi racoon: [192.168.100.4] INFO: Hashing 192.168.100.4[500] with algo #2
Jan 27 17:53:10 vivaldi racoon: INFO: NAT-D payload #0 verified
Jan 27 17:53:10 vivaldi racoon: [192.168.100.216] INFO: Hashing 192.168.100.216[500] with algo #2
Jan 27 17:53:10 vivaldi racoon: INFO: NAT-D payload #1 verified
Jan 27 17:53:10 vivaldi racoon: INFO: NAT not detected
Jan 27 17:53:10 vivaldi racoon: [192.168.100.216] INFO: Hashing 192.168.100.216[500] with algo #2
Jan 27 17:53:10 vivaldi racoon: [192.168.100.4] INFO: Hashing 192.168.100.4[500] with algo #2
Jan 27 17:53:10 vivaldi racoon: INFO: Adding remote and local NAT-D payloads.
Jan 27 17:53:11 vivaldi racoon: WARNING: unable to get certificate CRL(3) at depth:0 SubjectName:...
Jan 27 17:53:11 vivaldi racoon: WARNING: unable to get certificate CRL(3) at depth:1 SubjectName:...
Jan 27 17:53:11 vivaldi racoon: INFO: Sending Xauth request
Jan 27 17:53:11 vivaldi racoon: [192.168.100.216] INFO: received INITIAL-CONTACT
Jan 27 17:53:11 vivaldi racoon: INFO: ISAKMP-SA established 192.168.100.4[500]-192.168.100.216[500] spi:6aa3af26decd9581:805d7498a9bc9ed7
Jan 27 17:53:11 vivaldi racoon: ERROR: ignore information because the message is too short - 76 byte(s).

and the ipad displays a message "cannot verify server certificate" or
something like that.

Has anyone ever done this or set up successfully a vpn between ipad and
linux with another software than ipsec?

Bye and TIA,
Georg