setfib with mpd - ifconfig on p-t-p link trouble

[serg vasilyev]

Hi !
there's must be a restriction in ifconfig or in kernel that preventing from
adding a multiple p-t-p interface with same destination address.
i'm trying to build a test system with setfib and multiple mpd instances
which are creating PPPoE connection to same destination gateway and run into
problem with second p-t-p interface.
mpd did not add an IP and gateway for it

setfib 1 mpd1 -p /tmp/mpd1.pid -f mpd1.conf
sleep 2
 setfib 2 mpd2 -p /tmp/mpd2.pid -f mpd2.conf

on a first interface ng0 i have both src ip and dst ip but on second i have
nothing

# ifconfig ng0
ng0: flags=88d1<UP,POINTOPOINT,RUNNING,NOARP,SIMPLEX,MULTICAST> mtu 1492
        inet x.x.x.x --> y.y.y.y netmask 0xffffffff
# ifconfig ng1
ng1: flags=88d1<UP,POINTOPOINT,RUNNING,NOARP,SIMPLEX,MULTICAST> mtu 1492

when i try to add ip's personally
# ifconfig ng1 z.z.z.z y.y.y.y
ifconfig: ioctl (SIOCAIFADDR) File exist

 How to remove the given restriction on an ifconfig or kernel or something
else
P.S. Sorry for my english...