I have a working html email using modules: Mail System, HTML Mail, SMTP Authentication Support.
And I want to include some parameters/variables in the html email template file:
htmlmail--htmlmail.tpl.php
some variables include: $base_path
etc. from page.tpl.php
variables
From what I've read from the Internet, you may use "hooking" and I haven't yet hooked variables so far for my template file.