[exim] Exim & PHP

I'm trying to get PHP to send mail by using Exim as a local MTA.

I can manually send through exim from the command line but PHP can't. I
originally thought PHP wasn't finding Exim even though the sendmail_path
was set, but some quick work with the ps command shows it is infact
calling exim, but exim is ignoring the request and not writing anything to
the logs.

I suspect therefore it doesnt like the command syntax it's being called
with? PHP uses -t and -i by default but I cant see why these would be
causing a problem, unless it's something to do with -i and the way PHP is
indicating End of Message? - I have no idea how it does this! BTW

I've looked through the archives but cant' find anything and would
appreciate any suggestions.

Thanks