At the moment, my understanding is that MYOB relies on MAPI to send e'mails and if you are using an e'mail that does not use MAPI API's you have to save reports as, say PDF, and manually send by e'...
It looks like they may have solved for this problem.
http://help.myob.com/wiki/display/ar/Set+up+AccountRight+to+send+emails
I fear for me, it's a case of too little too late.