I tried with code that was shared by you in below post link, but unable to send email for the both end type EndAfterDate and EndAfterNOccurrences.
You can try with the code shared here(http://www.aspose.com/community/forums/showthread.aspx?PostID=633906&Subj=task-dates-and-recurrence-dates-no-recurrence-dates-property-available#633906).
Try to send task as email to an outlook account that is with Exchange Server.
Eventually I reached to this result if SMTP account type configured with outlook is POP3 then able to receive but if it configured with Exchange Server then it stop sending email. Not work properly as expected.
This is what i am expecting. Please share what is your thought on this?