Integration with opendmarc and postfix

Hi, I was trying to integrate pypolicyd-spf with postfix and opendmarc.

This is my configuration:
debugLevel = 1
defaultSeedOnly = 1

HELO_reject = False
Mail_From_reject = False

PermError_reject = False
TempError_Defer = False
Header_Type = AR
Authserv_Id = mail.bzone.it

skip_addresses = 127.0.0.0/8

master.cf line:
policyd-spf unix - n n - - spawn
     user=nobody argv=/usr/libexec/postfix/policyd-spf

main.cf:
smtpd_recipient_restrictions =
        ...
        check_policy_service unix:private/policyd-spf,
        ...

smtpd_milters = inet:localhost:8891,
                inet:localhost:8893,
                unix:/var/run/clamav/clamav-milter.sock,
                unix:/var/run/spamass-milter/postfix/sock

Where 8891 is opendkim milter and 8893 os opendmarc milter

Authentication-Results headers are correctly inserted:
Authentication-Results: mail.bzone.it; spf=pass (sender SPF authorized) smtp.mailfrom=apra.it (client-ip=89.97.236.28; helo=mail.apra.it; <email address hidden>; <email address hidden>)

But someway opendmarc always fails spf check according to the histoyfile...
job A81E914C021B
reporter mail.bzone.it
received 1395150648
ipaddr 89.97.236.28
from apra.it
mfrom apra.it
dkim apra.it 0
spf -1
pdomain apra.it
policy 15
rua -
pct 100
adkim 115
aspf 115
p 114
sp 114
align_dkim 4
align_spf 5
action 2

Environment:
Centos 6 x64
postfix 2.10
opendmarc 1.1.3
pypolicy-spf 1.2.3