ftp-server behind pf/nat

[milo974]

hello,

at work :
internet-->cisco modem router-->OpenBSD4.3 with PF/NAT-->servers

Internet ip address is fixe : 193.253.XXX.XXX
OpenBSD Gateway : 192.168.0.73(rl0) / 192.168.1.73 (fxp0)
Modem Router : 192.168.1.254
ftp-server : 192.168.0.88 (windows server 2003,iis)

Ports 21,20 are opened on cisco modem router (to openbsd gateway)
on OpenBSD Machine :
- added in rc.conf.local
ftpproxy_flags="-R 192.168.0.88 -p 21 -b 192.168.0.73"

- added theses lines in my pf.conf (my block policy, block in log on ext_if) :
nat-anchor "ftp-proxy/*"
rdr-anchor "ftp-proxy/*"
rdr on egress proto tcp from any to port 21 -> $ftp-server
rdr on egress proto tcp from any to port 20 -> $ftp-server
pass in quick on egress proto tcp to $ftp-server \
port 21
pass in quick on egress proto tcp to $ftp-server \
port 20

At home, i can't access ftp, in active mode or in passive mode (return me 192.168.0.88), someone can help me please ?