pptp filter rule problem

I have a new RB750, with this config for a VPN Windows client:

oct/22/2009 00:01:06 by RouterOS 3.30

software id = GYXW-U8RI

/ip firewall service-port
set pptp disabled=no

/interface pptp-server server
set authentication=mschap1,mschap2 default-profile=pptp-in enabled=yes keepalive-timeout=30 max-mru=1460
max-mtu=1460 mrru=disabled

/ppp secret
add caller-id=“” comment=“” disabled=no limit-bytes-in=0 limit-bytes-out=0 local-address=192.168.1.2 name=myuser
password=mypassword profile=pptp-in routes=“” service=any

/ip firewall filter
add action=accept chain=input comment=“default configuration” disabled=no protocol=icmp
add action=accept chain=input comment=“gre(47) pptp-in” disabled=no protocol=gre
add action=accept chain=input comment=“default configuration” connection-state=established disabled=no
in-interface=ether1-gateway
add action=accept chain=input comment=“default configuration” connection-state=related disabled=no in-interface=
ether1-gateway
add action=drop chain=input comment=“default configuration” disabled=no in-interface=ether1-gateway

And last filter rule blocks the pptp in. If i disable that last rule, the connection function ok, but leaves unprotect the interface. Howto permit only pptp in?.

Apart from GRE protocol PPTP also uses TCP port 1723, that is dropped by the last rule.