Overriding default tokens for mail notifications, such as !login_url or !site and sending html mail

Hi! I wanted to ask, is there any way to change values of !login_url, !username etc tokens when sending user mails (email confirmation, registration etc)?
I tried hooks, I tried modules with email tokens but all I want is to form email as html page and add token !login_url as link but not (for adding to my html template for email-greetings for new user, link for one-time login there will be formed as button).
Nothing worked. :(
Any suggestions?