DNAT sends packed by wrong interface

[Manuel Mollar Villanueva <mm@mobelt.com>]

Hi,
I have encountered a problem when using DNAT:

Scenario:

iptables v1.2.7a
Linux 2.4.20

Computer A:
   eth0 ip 150.128.49.236/21
   eth1 ip 10.1.1.1/24
   iptables -t nat -A PREROUTING -d 150.128.49.236 -p tcp --dport 8080 
-j DNAT --to-destination 10.1.1.2:80

Computer B:
  eth0 connected to eth1 of computer A, ip 10.1.1.2

Client C:
  ip 213.171.249.250
  When accessing port 8080 of A is redirected to port 80 on B,  OK

Client D:
  ip 150.128.49.219, in the SAME NETWORK of A (eth0)
  When connecting to A, port 8080, the configured DNAT redirects the 
packets to 10.1.1.2:80 , BUT PACKETS ARE SENT to interface ETH0, not to 
interface eth1 as expected, so , do not arrive to B.
  The same problem occurs for any client in the network of A

Some idea?

Thanks