Discovering peer engineID while sending INFORMS

Hi. I'm trying to develop a snmp sub-agent, and one of its missions is to
send informs to a Network Management System when an alarm/warning occurs in
our device.
I've found that when the first inform is not 'aknowledged' by the trap
receiving system (after 5 retries), the agent doesn't send any inform to it
anymore.  After that, this message appears in the log everytime a new inform
need to be sent: "snmpd: send_trap: USM unknown security name (no such user
exists)"
After digging deeply into the code I've found that the agent only tries to
discover the peer engineID once per 'session':
send_v2trap -> send_trap_vars -> send_enterprise_trap_vars ->
netsnmp_send_traps -> send_trap_to sess -> snmp_async_send ->
snmp_sess_async_send -> _sess_async_send   calls to snmpv3_engineID_probe.
This function sets the session->flags SNMP_FLAGS_DONT_PROBE to prevent
recursion... but if the remote engine doesn't answer, this flag remains
set.  And, later, if a new inform needs to be sent the agent doesn't retry
to obtain the engineID again.

I've detected this behaviour using net-snmp versions 5.3.0.1 and
5.3.1libraries in a subagent module through agentx (SNMPV3) running on
Linux.
Is this behaviour correct?  Shouldn't the agent keep trying to obtain the
engineID of the receiver if the previous communication failed?

To correct this I've done the following modification (turn off the flag
SNMP_FLAG_DONT_PROBE if we have no answer) in function snmpv3_engineID_probe
in snmplib/snmp_api.c

            if (slp->session->securityEngineIDLen == 0) {
                DEBUGMSGTL(("snmp_api",
                            "unable to determine remote engine ID\n"));
            session->flags &= ~SNMP_FLAGS_DONT_PROBE; /* EBP */
                return 0;
            }

But this modification provoques two effects: 1) the engineID is requested
for every inform while we have no answer from the receiver (OK ;)))).
2)The informs are repeated a lot of times when the receiver acknowledge them
(BAD!!!).

My snmpd.conf ...
createUser snmp_usr MD5 snmp_pass
trapsess -C i -v 3 -u snmp_usr -a MD5 -A snmp_pass -l authNoPriv
172.16.2.5:162

Any comments would be appreciated..
Thanks in advance.
Enric.

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