sendmailR: Submit encoded message to local SMTP server - email

Question

I need your help in order to send email message that includes text in Greek, from within R, using the function sendmail {sendmailR}.
I tried using the function iconv, like that but it didn't work
subject <- iconv("text in greek", to = "CP1253")
sendmail(from, to, subject, msg, control=list(smtpServer="blabla"))
The mail arrives immediately but the greek characters are unreadable. Any ideas?
EDIT
Another question that came up:
The second argument to accepts one recipient. What if want to send it to more than one? (I think 'll try sapply ing the sendmail function to a vector of recipients) - Ok, that worked. However, I'm not completely satisfied because each one of the recipients has no way to know who else has received the message.

Answer 1

Mail client won't be able to understand any encoding without Content-Type: charset=..., so you must add it:
msg<-iconv("text in greek", to = "utf8");
sendmail(from, to, subject, msg,
control=list(smtpServer="blabla"),
headers=list("Content-Type"="text/plain; charset=UTF-8; format=flowed")
);
that is for UTF8 (which I believe should be used), for CP1253:
msg<-iconv("text in greek", to = "CP1253");
sendmail(from, to, subject, msg,
control=list(smtpServer="blabla"),
headers=list("Content-Type"="text/plain; charset=CP1253; format=flowed")
);
multisend by hidden copies can also be done with header magick, still I think sapply loop is a better idea -- then the user will see that the mail was send directly to her/himself.