I have been selling on E-Junkie for nearly two years now, and have personally done all the shopping cart integration into my e-commerce website. You can see how I integrated everything by visiting http://www.Pediasleep.com and taking a look at the individual sounds that my company sells.
Getting started on E-Junkie can have a steep learning curve that can leave you scratching your head and frustrated at times (been there, done that), but you are very correct that it's indeed "simple stuff" once you get the hang of it.
What you want to do sounds like something that would be very simple to explain for someone who has experience with E-Junkie. Compared with learning how to do it yourself though, I bet a consult would save you at least a couple hours of work.
I would be happy to provide the "hand-holding" you are looking for, and take the time to walk you through the steps in a phone or web consult session.
Please send me an email by clicking on my user profile on the top left of this post, if you're interested.