How to set up spooling for a HP JetDirect interface?

[Tulipant-Gergely at dbrt.hu]

I've set up Samba and LPRng for HP printers with 
JetDirect cards. It works for one user at a 
time. But if the printer is off-line or busy, the
samba client does not get an error message, but 
the job gets lost. :( I would like the print 
jobs to be spooled on Linux even when there is an
active print job or when the printer is off-line.
Unfortunately I'm not familiar with lpd.

The relevant lines from smb.conf:

[global]
   load printers = no
   printing = lprng

[HP4Plus]
   public = yes
   browsable = yes
   writable = no
   create mode = 0700
   printable = yes
   path = /mnt/sda5/samba/print
   print command = /usr/local/bin/lpr -P at x.x.x.x 
-r -h %s;rm %s
   lpq command   = /usr/local/bin/lpq -P at x.x.x.x
   lprm command  = /usr/local/bin/lprm -
P at x.x.x.x %j
   printer driver = HP LaserJet 4 Plus

I've tried to set up /etc/printcap and printing 
with lpr, but it worked the same way, whatever I 
did.

The latest version is:

hp4plus
    :rw:sh:mx#0:sd=/var/spool/lpd/hp4plus
    :rm=hp4plus
    :send_failure_action=retry
    :send_try#0
    :send_rw_timout#0
    :retry_econrefused=true
    :connect_timeout#0


The system is based on Linux RedHat 5.2 and 
samba-1.9.18p10-5.

I don't need to print from the Linux shell, only 
thru Samba.