ip vs. route

Hi folks,

I notice a strange behaviour on my freewrt box. I set up a vpn with openvpn
and need to set some routes through my network.

Following I try with route:

root@gtw01:/etc# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use
Iface
10.101.66.240   0.0.0.0         255.255.255.240 U     0      0        0
eth0.0
10.104.125.0    0.0.0.0         255.255.255.0   U     0      0        0
eth1
0.0.0.0         0.0.0.0         0.0.0.0         U     0      0        0
ppp0
root@gtw01:/etc# route add -host 10.101.66.253 dev eth0.0
root@gtw01:/etc# route add -net 10.8.0.0 netmask 255.255.255.0 gw
10.101.66.253 dev eth0.0
root@gtw01:/etc# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use
Iface
10.101.66.253   0.0.0.0         255.255.255.255 UH    0      0        0
eth0.0
10.101.66.240   0.0.0.0         255.255.255.240 U     0      0        0
eth0.0
10.104.125.0    0.0.0.0         255.255.255.0   U     0      0        0
eth1
10.8.0.0        10.101.66.253   255.255.255.0   UG    0      0        0
eth0.0
0.0.0.0         0.0.0.0         0.0.0.0         U     0      0        0
ppp0

Everything works like a charm. But with ip I get this:

root@gtw01:/etc# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use
Iface
10.101.66.240   0.0.0.0         255.255.255.240 U     0      0        0
eth0.0
10.104.125.0    0.0.0.0         255.255.255.0   U     0      0        0
eth1
0.0.0.0         0.0.0.0         0.0.0.0         U     0      0        0
ppp0
root@gtw01:/etc# ip route add 10.101.66.253 dev eth0.0
root@gtw01:/etc# ip route add 10.8.0.0 via 10.101.66.253 dev eth0.0
ip: RTNETLINK answers: Network is unreachable

I need ip for maintain my ruleset with fwbuilder.
Who can give me a hint?

Thanks.
Kamill