token node nid

Hello,

I am using the rules module (6.x-1.4) for a few time and I don't understand how to get the [node:nid] token with "content is going to be saved" event

Detaills of rules elements

If
User has role (role defined => ok)
Save content is (content type defined => ok)

do
send email

In the message field, I would like to write the internal url of drupal like this
http://mydomain.com/node/[node:nid]/edit

but [node:nid] is not defined, why ?

In another rule defined with "After updating existing content" event, no problem, the [node:nid] token is well defined.