Ipsec tunnel between cisco 3640 and 3660

[luthierone]

Hello,
I am setting up a vpn between the above routers. I am using the VTI method with a tunnel interface. I have the tunnel up right now using the default GRE mode. Now I want to use ipsec, I have everything set up but need to turn on ipsec for the tunnel mode. The command for this is:
"tunnel mode ipsec ipv4"
This works on the 3640, however this option isn't listed in the 3660. Here is what I get doing a "tunnel mode ?"
aurp AURP TunnelTalk AppleTalk encapsulation
cayman Cayman TunnelTalk AppleTalk encapsulation
dvmrp DVMRP multicast tunnel
eon EON compatible CLNS tunnel
gre generic route encapsulation protocol
ipip IP over IP encapsulation
iptalk Apple IPTalk encapsulation
ipv6ip IPv6 over IP encapsulation
mpls MPLS encapsulations
nos IP over IP encapsulation (KA9Q/NOS compatible)

I also noticed that the:
"show crypto session"
command isn't available on the 3660 but is on the 3640.

The second command I need:
"tunnel protection ipsec profile"
works on both routers, but the tunnel won't come back up because one side is gre and the other is ipsec.

The ios version of the 3660 is 12.3(17a)
The ios version of the 3640 is 12.4(3a)

The 3660 is also running a AIM-VPN/HP module, the 3640 isn't running an ecryption card.

thank you,