[Samba] [samba] printer & cups

[root]

my samba is working good, only a problem with the classic pdf printer

I get this message from testparm

Warning: Service pdf-printer defines a print command, but print command parameter is ignored when using CUPS libraries.
Server role: ROLE_STANDALONE
Press enter to see a dump of your service definitions


and this is my .conf

[global]
        workgroup = RSA
        netbios name = RSA-INTRANET
        server string = RSA-INTRANET
        map to guest = Bad User
        passdb backend = tdbsam
        log file = /var/log/samba/log.%m
        dns proxy = No

[pubblico]
        comment = condivisione pubblica
        path = /var/pubblico
        read only = No

[pdf-printer]
        path = /var/pubblico/
        create mask = 0700
        guest ok = Yes
        printable = Yes
        print command = /usr/bin/printpdf.sh %s
        printer name = lp

everyt hings works ok, but the print command isn't executed altough the printer is shared and visible on the lan.

thanks for any help