Hi!
On mesh router connected to ADSL:
batmand -g 1000 ath0
On other mesh router:
batmand -r 1 ath0
You have to NAT towards the internet on the gateway.
There is a bug in batmand in current 0.3.2 code, which occurs when you use HNA (-a). We are currently working on it. You don't need to use -a to connect to the internet in your case, however. But you have to set up simple NAT towards the interface of the batman-gateway connected to the ADSL modem.
If that interface is eth0 the command would be:
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
Cheers, elektra