Email template {!:;} Not working

Hi All,

I read in this blog https://community.dynamics.com/crm/f/117/t/201584

that it is possible to add fields from another entity in email template. But it is not working for me

My scenario is:

1. Created the template for Order Entity

2. I want few fields from opportunity inside it

3. Sender receiver and regarding object is set using javascript

4. Regarding object is order entity record

5. Now according to the suggestion I am adding opportunity fields like this {!opportunity:name;}

6.That turns yellow 

7. But when I run the code, it doesn't show any value

What I am doing wrong? It is something with regarding object or relation between entities or unsupported issue?

Anybody has another way to do it.