Need help in "how to give token value on form submission"..?

Hello There,
I am facing a simple but strange issue.

I have a node form and i want a token that have the node URL that is being submitted/created. I want to send a thank you message to the user along with the node link.

I have created a custom token using hook_token_info (https://api.drupal.org/api/drupal/modules%21system%21system.api.php/func...) and given the value using hook_tokens (https://api.drupal.org/api/drupal/modules%21system%21system.api.php/func... ). But, i am unable to change/assign the value of the token at node_form_submit.

The last option is to use the str_replace (http://php.net/manual/en/function.str-replace.php) function of PHP. But i do not want to do it in a dirty manner.

Any Idea how to achieve this.?

Thanks and Regards
Tarun Nagpal