Configure BGP multihop with version 1.6.8 not working

[Wei Huang]

I am testing with Bird 1.6.8 with the following setup

Box 1 with interface VPP0 (192.168.1.6) ----------R--------Box 2 with interface 
VPP0 (192.168.2.6)
Middle router R has IP address 192.168.1.1 and 192.168.2.1
The config for Box 1:

table T0;

# This pseudo-protocol watches all interface up/down events.
protocol device {
        scan time 10;           # Scan interfaces every 10 seconds
}

# Configure logging
log "/home/talariuser/log/dynamic_routing.log" { debug, trace, info, remote, 
warning, error, auth, fatal, bug } ;

router id 198.168.100.5;

protocol static {
        table T0;
        check link;
        route 192.168.2.0/24 via 192.168.1.1; # Default route
        import all;
        export all;
}

protocol bgp bgp1 {
        table T0;
        import all;
        # Do not change this parameters without assistance
        gateway recursive;
        next hop self;
        local as 100;
        hold time 180;
        source address 192.168.1.6;
        default bgp_local_pref 100;
        igp metric on;
        neighbor 192.168.2.6 as 100;
        multihop 3;
        import all;
        export all;

}
protocol direct {
        table T0;
        interface "vpp0";
}

Similar on box2. The BGP stay in connect state. When I try to do packet capture 
on interface "vpp0", I don't see any packets sent out.

Anybody can point out what I did wrong in the config?

Thanks in advance,

Wei