>I do not see the "mail" button. Where is the option to send private messages?
It's in the top right, next to your name.
If you're having questions on how the Forum works, you should first look a the FAQs:
http://h30499.www3.hp.com/t5/help/faqpage
http://h30499.www3.hp.com/t5/custom/page/page-id/faq_ui
And post your questions in: Community Feedback & Suggestions
http://h30499.www3.hp.com/t5/Community-Feedback-Suggestions/bd-p/community-feedback-suggestions