Msmapi works pretty good. There are some good examples on MS KB. Below details how to reply to a message in the inbox.

osession = createobject('msmapi.mapisession')
omessage = createobject('msmapi.mapimessages')

osession.signon
omessage.sessionid = form1.osession.sessionid
omessage.fetch

do while omessage.msgcount > 0
omessage.msgindex = form1.omessage.msgcount - 1
omessage.reply
omessage.send(.f.)
enddo

release osession
release omessage