The SMTP standard (both RFC 821 and RFC 2821) clearly states that the argument to the HELO/EHLO message must be the local—not remote—hostname. In fact, RFC 821 even paraphrases that in plain English too: “saying "Hello, I am <domain>"”.
Everyone that makes a program which violates this rule—and therefore causes the server that runs the program to be blacklisted as a spam host—needs to be whipped. Badly. -_-++++
P.S. There's an exception: Spam engine authors should continue using broken HELO/EHLO messages. -_-