Jr. Sysadmin Job Description?

I have been given a chance to update my current job description that would help pave the way for future advancement. Currently I am Desktop Support/Helpdesk but have in the past year been taking on more responsibilities, especially with regards to more stringent security. A sysadmin or jr. sysadmin position does not exist. The next position up from Helpdesk is Engineer.

Would love to get input on a JD that would show my management that there is a need and provide applicable duties/skills that would justify a potential new position.