Only by amending core code.
However, this bookmark leaps out at me for the second question, and I suspect is a pretty good start on the first: https://developer.atlassian.com/display/JIRADEV/Plugin+Tutorial+-+Adding+Content+to+the+JIRA+View+Issue+Page
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.