[exim] Queue (or not) on flash devices

Hi,

I'm using small tiny embedded devices as inbound mail server for first
spam fighting and anti-virus job. All the system run in memory, and
with clamav, system use 150 MB, no write on compact flash as it's
really not dedicated and really slow. Currently the solution is based on
postfix/clamav/clamsmtp. I'm really get bored of postfix and its really
crap config and side effects as lost mail, memory comsuption.

As I really like exim, I'm looking to replace postfix by exim in that
devices.

I would like to known if there is a way to not queue at all. As
example, I've two big mails in queue as network is down with imap
server, reboot is cause by watchdog because another processus eat
memory. The two mails are lost.

So can I send {2,4,5}00 to external server only when mail have been
treated by transports and really send to backend storage server ?

Thanks,

--
Beber