I have the same issue. I have tried to set the subject several times and it never works. I have tried it with and without spaces, with upper and lowercase and it still doesn't work. I followed the same guide you did.

That's strange, I tried it with 1st Sept and 1st September and got it to come over O.K. using the full descriptor of "Due:"

Do you think it voulf be the short descriptor of "D:" that causes the issue?

The body of the e-mail was as follows (I use Outlook and a "Signature" template with all of the RTM fields, I just filled out the Due Date):
#1 example

Priority:

Due: 1st Sept

Repeat:

Estimate:

Tags:

Location:

URL:

List:

---
[Notes go here]

---

-end-

#2 Example

Priority:

Due: 1st September

Repeat:

Estimate:

Tags:

Location:

URL:

List:

---
[Notes go here]

---

-end-

I have exactly the same problem.

The issue appears to be with using shortcuts within the body such as "D: today at 10am". When use the full tags such as "Due: today at 10am" it works perfectly.

Something to add to the bug list possibly?

OK a bit more investigation has got to the bottom of this.

If you are using something like a Blackberry, remember that it automatically adds a signature to every email it sends, even though you don't see it on the screen. This appears to be c what was causing my problems.

If you ensure you add -end- at the end of the body of your email this should solve the problem and will mean that the shortcuts such as d: for due work :)

I think this should be going straight to the FAQ.

I had the same issue (task properties ignored when sending tasks by email and using shortcuts).

Thanks for sorting things out!

BTW an almost "classic" fix for the RTM team would be to parse the pre-HTML signature seperator (i.e. "-- ") as a message terminator.