Hi,
You need to by pass NAT for the traffic from the LAN to the VPN Client Pool.
access-list 150 deny ip 192.168.168.0 0.0.0.255 172.30.50.0 0.0.0.255
access-list 150 permit ip 192.168.168.0 0.0.0.255 any
ip nat inside source list 100 interface dialer0 overload
So, in the above example, any traffic sources from 192.168.168.0/24 destined to 172.30.50.0/24 is not NATted.
Please refer the below URL for details.
http://www.cisco.com/en/US/tech/tk583/tk372/technologies_configuration_example09186a008009475c.shtml
I hope it helps.
Regards,
Arul