Here is my config file:

log syslog all;

router id 91.aaa.aaa.1;

protocol device {
        scan time 15;
}

protocol kernel {
        export all;
        scan time 15;
}

protocol static {
        route 91.aaa.aaa.0/24 reject;
        route 91.kkk.kkk.0/22 reject;
}

filter bgp_out
{
    if net = 91.aaa.aaa.0/24 then accept;
    else reject;
}

protocol bgp bgp_bdi {
    description "BDI";
    import all;
    local as 57zzz;
    neighbor 83.bbb.bbb.21 as 12nnn;
    source address 83.bbb.bbb.22;
    export filter {
        if source = RTS_STATIC then {
            bgp_path.prepend(57zzz);
            accept;
        }
        reject;
    };
}

protocol bgp bgp_vop {
    description "Vop";
    import all;
    export filter {
        if source = RTS_STATIC then {
            accept;
        }
        reject;
    };
    local as 57zzz;
    neighbor 109.xxx.xxx.77 as 50yyy;
    source address 109.xxx.xxx.78;
    default bgp_local_pref 200;
}

Now I want add second ASN, which must communicate with 57zzz.

--
Miłosz
Dnia 2012-03-24, sob o godzinie 15:49 +0400, Oleg pisze: 
On Sat, Mar 24, 2012 at 09:00:34AM +0100, Mi??osz Oller wrote:
> Hi

  Hi.

> How can I run two asn on one router?
> 
> Example:
> 
>   ISP1 
>      |
> ---------------
> | AS1 - AS2 |
> ---------------
>                |
>             ISP2
> 
> ISP1 is connected to AS1, ISP2 is connected to AS2. How can I configure
> connection AS1-AS2 with bgp protocol on localhost (neighbor ip and
> source address)? 

  What about local option of bgp protocol?
http://bird.network.cz/?get_doc&f=bird-6.html#ss6.1