Round-robin + NAT on 2 public interfaces, is it possible?

[Rafal Rajko-Nenow]

my network:

           tun0:213.77.157.164   tun1:213.77.157.139
                       |               |
                       |               |
                ------------------------------
                | FreeBSD box.               |
                | rl0: 10.0.0.0/16	     |
		| internal ip: 10.0.0.1      |
                ------------------------------
                rl0:
                |
                |
                ------ windows box 10.0.1.1
		|
		|
		------ windows box 10.0.1.2
		|
		|
		------ windows box 10.0.2.1
		|
		|
		------ windows box 10.0.2.2

	I have tried to NAT 10.0.1.0/24 subnet on tun0, and the second subnet
(10.0.2.0/24) on tun1. It won't work - NAT works only on my default routing
interface, although there is no way to set up 2 default routes.
	I cannot use any routing protocol, because of my ISP.

	And I need any load balancing between both of tun interfaces (TCP 
support.)

	I'll be pleased for any help on this subject.